xref: /freebsd/contrib/llvm-project/clang/lib/Parse/ParseExpr.cpp (revision 19261079b74319502c6ffa1249920079f0f69a72)
1 //===--- ParseExpr.cpp - Expression Parsing -------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 ///
9 /// \file
10 /// Provides the Expression parsing implementation.
11 ///
12 /// Expressions in C99 basically consist of a bunch of binary operators with
13 /// unary operators and other random stuff at the leaves.
14 ///
15 /// In the C99 grammar, these unary operators bind tightest and are represented
16 /// as the 'cast-expression' production.  Everything else is either a binary
17 /// operator (e.g. '/') or a ternary operator ("?:").  The unary leaves are
18 /// handled by ParseCastExpression, the higher level pieces are handled by
19 /// ParseBinaryExpression.
20 ///
21 //===----------------------------------------------------------------------===//
22 
23 #include "clang/Parse/Parser.h"
24 #include "clang/AST/ASTContext.h"
25 #include "clang/AST/ExprCXX.h"
26 #include "clang/Basic/PrettyStackTrace.h"
27 #include "clang/Parse/RAIIObjectsForParser.h"
28 #include "clang/Sema/DeclSpec.h"
29 #include "clang/Sema/ParsedTemplate.h"
30 #include "clang/Sema/Scope.h"
31 #include "clang/Sema/TypoCorrection.h"
32 #include "llvm/ADT/SmallVector.h"
33 using namespace clang;
34 
35 /// Simple precedence-based parser for binary/ternary operators.
36 ///
37 /// Note: we diverge from the C99 grammar when parsing the assignment-expression
38 /// production.  C99 specifies that the LHS of an assignment operator should be
39 /// parsed as a unary-expression, but consistency dictates that it be a
40 /// conditional-expession.  In practice, the important thing here is that the
41 /// LHS of an assignment has to be an l-value, which productions between
42 /// unary-expression and conditional-expression don't produce.  Because we want
43 /// consistency, we parse the LHS as a conditional-expression, then check for
44 /// l-value-ness in semantic analysis stages.
45 ///
46 /// \verbatim
47 ///       pm-expression: [C++ 5.5]
48 ///         cast-expression
49 ///         pm-expression '.*' cast-expression
50 ///         pm-expression '->*' cast-expression
51 ///
52 ///       multiplicative-expression: [C99 6.5.5]
53 ///     Note: in C++, apply pm-expression instead of cast-expression
54 ///         cast-expression
55 ///         multiplicative-expression '*' cast-expression
56 ///         multiplicative-expression '/' cast-expression
57 ///         multiplicative-expression '%' cast-expression
58 ///
59 ///       additive-expression: [C99 6.5.6]
60 ///         multiplicative-expression
61 ///         additive-expression '+' multiplicative-expression
62 ///         additive-expression '-' multiplicative-expression
63 ///
64 ///       shift-expression: [C99 6.5.7]
65 ///         additive-expression
66 ///         shift-expression '<<' additive-expression
67 ///         shift-expression '>>' additive-expression
68 ///
69 ///       compare-expression: [C++20 expr.spaceship]
70 ///         shift-expression
71 ///         compare-expression '<=>' shift-expression
72 ///
73 ///       relational-expression: [C99 6.5.8]
74 ///         compare-expression
75 ///         relational-expression '<' compare-expression
76 ///         relational-expression '>' compare-expression
77 ///         relational-expression '<=' compare-expression
78 ///         relational-expression '>=' compare-expression
79 ///
80 ///       equality-expression: [C99 6.5.9]
81 ///         relational-expression
82 ///         equality-expression '==' relational-expression
83 ///         equality-expression '!=' relational-expression
84 ///
85 ///       AND-expression: [C99 6.5.10]
86 ///         equality-expression
87 ///         AND-expression '&' equality-expression
88 ///
89 ///       exclusive-OR-expression: [C99 6.5.11]
90 ///         AND-expression
91 ///         exclusive-OR-expression '^' AND-expression
92 ///
93 ///       inclusive-OR-expression: [C99 6.5.12]
94 ///         exclusive-OR-expression
95 ///         inclusive-OR-expression '|' exclusive-OR-expression
96 ///
97 ///       logical-AND-expression: [C99 6.5.13]
98 ///         inclusive-OR-expression
99 ///         logical-AND-expression '&&' inclusive-OR-expression
100 ///
101 ///       logical-OR-expression: [C99 6.5.14]
102 ///         logical-AND-expression
103 ///         logical-OR-expression '||' logical-AND-expression
104 ///
105 ///       conditional-expression: [C99 6.5.15]
106 ///         logical-OR-expression
107 ///         logical-OR-expression '?' expression ':' conditional-expression
108 /// [GNU]   logical-OR-expression '?' ':' conditional-expression
109 /// [C++] the third operand is an assignment-expression
110 ///
111 ///       assignment-expression: [C99 6.5.16]
112 ///         conditional-expression
113 ///         unary-expression assignment-operator assignment-expression
114 /// [C++]   throw-expression [C++ 15]
115 ///
116 ///       assignment-operator: one of
117 ///         = *= /= %= += -= <<= >>= &= ^= |=
118 ///
119 ///       expression: [C99 6.5.17]
120 ///         assignment-expression ...[opt]
121 ///         expression ',' assignment-expression ...[opt]
122 /// \endverbatim
123 ExprResult Parser::ParseExpression(TypeCastState isTypeCast) {
124   ExprResult LHS(ParseAssignmentExpression(isTypeCast));
125   return ParseRHSOfBinaryExpression(LHS, prec::Comma);
126 }
127 
128 /// This routine is called when the '@' is seen and consumed.
129 /// Current token is an Identifier and is not a 'try'. This
130 /// routine is necessary to disambiguate \@try-statement from,
131 /// for example, \@encode-expression.
132 ///
133 ExprResult
134 Parser::ParseExpressionWithLeadingAt(SourceLocation AtLoc) {
135   ExprResult LHS(ParseObjCAtExpression(AtLoc));
136   return ParseRHSOfBinaryExpression(LHS, prec::Comma);
137 }
138 
139 /// This routine is called when a leading '__extension__' is seen and
140 /// consumed.  This is necessary because the token gets consumed in the
141 /// process of disambiguating between an expression and a declaration.
142 ExprResult
143 Parser::ParseExpressionWithLeadingExtension(SourceLocation ExtLoc) {
144   ExprResult LHS(true);
145   {
146     // Silence extension warnings in the sub-expression
147     ExtensionRAIIObject O(Diags);
148 
149     LHS = ParseCastExpression(AnyCastExpr);
150   }
151 
152   if (!LHS.isInvalid())
153     LHS = Actions.ActOnUnaryOp(getCurScope(), ExtLoc, tok::kw___extension__,
154                                LHS.get());
155 
156   return ParseRHSOfBinaryExpression(LHS, prec::Comma);
157 }
158 
159 /// Parse an expr that doesn't include (top-level) commas.
160 ExprResult Parser::ParseAssignmentExpression(TypeCastState isTypeCast) {
161   if (Tok.is(tok::code_completion)) {
162     Actions.CodeCompleteExpression(getCurScope(),
163                                    PreferredType.get(Tok.getLocation()));
164     cutOffParsing();
165     return ExprError();
166   }
167 
168   if (Tok.is(tok::kw_throw))
169     return ParseThrowExpression();
170   if (Tok.is(tok::kw_co_yield))
171     return ParseCoyieldExpression();
172 
173   ExprResult LHS = ParseCastExpression(AnyCastExpr,
174                                        /*isAddressOfOperand=*/false,
175                                        isTypeCast);
176   return ParseRHSOfBinaryExpression(LHS, prec::Assignment);
177 }
178 
179 /// Parse an assignment expression where part of an Objective-C message
180 /// send has already been parsed.
181 ///
182 /// In this case \p LBracLoc indicates the location of the '[' of the message
183 /// send, and either \p ReceiverName or \p ReceiverExpr is non-null indicating
184 /// the receiver of the message.
185 ///
186 /// Since this handles full assignment-expression's, it handles postfix
187 /// expressions and other binary operators for these expressions as well.
188 ExprResult
189 Parser::ParseAssignmentExprWithObjCMessageExprStart(SourceLocation LBracLoc,
190                                                     SourceLocation SuperLoc,
191                                                     ParsedType ReceiverType,
192                                                     Expr *ReceiverExpr) {
193   ExprResult R
194     = ParseObjCMessageExpressionBody(LBracLoc, SuperLoc,
195                                      ReceiverType, ReceiverExpr);
196   R = ParsePostfixExpressionSuffix(R);
197   return ParseRHSOfBinaryExpression(R, prec::Assignment);
198 }
199 
200 ExprResult
201 Parser::ParseConstantExpressionInExprEvalContext(TypeCastState isTypeCast) {
202   assert(Actions.ExprEvalContexts.back().Context ==
203              Sema::ExpressionEvaluationContext::ConstantEvaluated &&
204          "Call this function only if your ExpressionEvaluationContext is "
205          "already ConstantEvaluated");
206   ExprResult LHS(ParseCastExpression(AnyCastExpr, false, isTypeCast));
207   ExprResult Res(ParseRHSOfBinaryExpression(LHS, prec::Conditional));
208   return Actions.ActOnConstantExpression(Res);
209 }
210 
211 ExprResult Parser::ParseConstantExpression(TypeCastState isTypeCast) {
212   // C++03 [basic.def.odr]p2:
213   //   An expression is potentially evaluated unless it appears where an
214   //   integral constant expression is required (see 5.19) [...].
215   // C++98 and C++11 have no such rule, but this is only a defect in C++98.
216   EnterExpressionEvaluationContext ConstantEvaluated(
217       Actions, Sema::ExpressionEvaluationContext::ConstantEvaluated);
218   return ParseConstantExpressionInExprEvalContext(isTypeCast);
219 }
220 
221 ExprResult Parser::ParseCaseExpression(SourceLocation CaseLoc) {
222   EnterExpressionEvaluationContext ConstantEvaluated(
223       Actions, Sema::ExpressionEvaluationContext::ConstantEvaluated);
224   ExprResult LHS(ParseCastExpression(AnyCastExpr, false, NotTypeCast));
225   ExprResult Res(ParseRHSOfBinaryExpression(LHS, prec::Conditional));
226   return Actions.ActOnCaseExpr(CaseLoc, Res);
227 }
228 
229 /// Parse a constraint-expression.
230 ///
231 /// \verbatim
232 ///       constraint-expression: C++2a[temp.constr.decl]p1
233 ///         logical-or-expression
234 /// \endverbatim
235 ExprResult Parser::ParseConstraintExpression() {
236   EnterExpressionEvaluationContext ConstantEvaluated(
237       Actions, Sema::ExpressionEvaluationContext::Unevaluated);
238   ExprResult LHS(ParseCastExpression(AnyCastExpr));
239   ExprResult Res(ParseRHSOfBinaryExpression(LHS, prec::LogicalOr));
240   if (Res.isUsable() && !Actions.CheckConstraintExpression(Res.get())) {
241     Actions.CorrectDelayedTyposInExpr(Res);
242     return ExprError();
243   }
244   return Res;
245 }
246 
247 /// \brief Parse a constraint-logical-and-expression.
248 ///
249 /// \verbatim
250 ///       C++2a[temp.constr.decl]p1
251 ///       constraint-logical-and-expression:
252 ///         primary-expression
253 ///         constraint-logical-and-expression '&&' primary-expression
254 ///
255 /// \endverbatim
256 ExprResult
257 Parser::ParseConstraintLogicalAndExpression(bool IsTrailingRequiresClause) {
258   EnterExpressionEvaluationContext ConstantEvaluated(
259       Actions, Sema::ExpressionEvaluationContext::Unevaluated);
260   bool NotPrimaryExpression = false;
261   auto ParsePrimary = [&] () {
262     ExprResult E = ParseCastExpression(PrimaryExprOnly,
263                                        /*isAddressOfOperand=*/false,
264                                        /*isTypeCast=*/NotTypeCast,
265                                        /*isVectorLiteral=*/false,
266                                        &NotPrimaryExpression);
267     if (E.isInvalid())
268       return ExprError();
269     auto RecoverFromNonPrimary = [&] (ExprResult E, bool Note) {
270         E = ParsePostfixExpressionSuffix(E);
271         // Use InclusiveOr, the precedence just after '&&' to not parse the
272         // next arguments to the logical and.
273         E = ParseRHSOfBinaryExpression(E, prec::InclusiveOr);
274         if (!E.isInvalid())
275           Diag(E.get()->getExprLoc(),
276                Note
277                ? diag::note_unparenthesized_non_primary_expr_in_requires_clause
278                : diag::err_unparenthesized_non_primary_expr_in_requires_clause)
279                << FixItHint::CreateInsertion(E.get()->getBeginLoc(), "(")
280                << FixItHint::CreateInsertion(
281                    PP.getLocForEndOfToken(E.get()->getEndLoc()), ")")
282                << E.get()->getSourceRange();
283         return E;
284     };
285 
286     if (NotPrimaryExpression ||
287         // Check if the following tokens must be a part of a non-primary
288         // expression
289         getBinOpPrecedence(Tok.getKind(), GreaterThanIsOperator,
290                            /*CPlusPlus11=*/true) > prec::LogicalAnd ||
291         // Postfix operators other than '(' (which will be checked for in
292         // CheckConstraintExpression).
293         Tok.isOneOf(tok::period, tok::plusplus, tok::minusminus) ||
294         (Tok.is(tok::l_square) && !NextToken().is(tok::l_square))) {
295       E = RecoverFromNonPrimary(E, /*Note=*/false);
296       if (E.isInvalid())
297         return ExprError();
298       NotPrimaryExpression = false;
299     }
300     bool PossibleNonPrimary;
301     bool IsConstraintExpr =
302         Actions.CheckConstraintExpression(E.get(), Tok, &PossibleNonPrimary,
303                                           IsTrailingRequiresClause);
304     if (!IsConstraintExpr || PossibleNonPrimary) {
305       // Atomic constraint might be an unparenthesized non-primary expression
306       // (such as a binary operator), in which case we might get here (e.g. in
307       // 'requires 0 + 1 && true' we would now be at '+', and parse and ignore
308       // the rest of the addition expression). Try to parse the rest of it here.
309       if (PossibleNonPrimary)
310         E = RecoverFromNonPrimary(E, /*Note=*/!IsConstraintExpr);
311       Actions.CorrectDelayedTyposInExpr(E);
312       return ExprError();
313     }
314     return E;
315   };
316   ExprResult LHS = ParsePrimary();
317   if (LHS.isInvalid())
318     return ExprError();
319   while (Tok.is(tok::ampamp)) {
320     SourceLocation LogicalAndLoc = ConsumeToken();
321     ExprResult RHS = ParsePrimary();
322     if (RHS.isInvalid()) {
323       Actions.CorrectDelayedTyposInExpr(LHS);
324       return ExprError();
325     }
326     ExprResult Op = Actions.ActOnBinOp(getCurScope(), LogicalAndLoc,
327                                        tok::ampamp, LHS.get(), RHS.get());
328     if (!Op.isUsable()) {
329       Actions.CorrectDelayedTyposInExpr(RHS);
330       Actions.CorrectDelayedTyposInExpr(LHS);
331       return ExprError();
332     }
333     LHS = Op;
334   }
335   return LHS;
336 }
337 
338 /// \brief Parse a constraint-logical-or-expression.
339 ///
340 /// \verbatim
341 ///       C++2a[temp.constr.decl]p1
342 ///       constraint-logical-or-expression:
343 ///         constraint-logical-and-expression
344 ///         constraint-logical-or-expression '||'
345 ///             constraint-logical-and-expression
346 ///
347 /// \endverbatim
348 ExprResult
349 Parser::ParseConstraintLogicalOrExpression(bool IsTrailingRequiresClause) {
350   ExprResult LHS(ParseConstraintLogicalAndExpression(IsTrailingRequiresClause));
351   if (!LHS.isUsable())
352     return ExprError();
353   while (Tok.is(tok::pipepipe)) {
354     SourceLocation LogicalOrLoc = ConsumeToken();
355     ExprResult RHS =
356         ParseConstraintLogicalAndExpression(IsTrailingRequiresClause);
357     if (!RHS.isUsable()) {
358       Actions.CorrectDelayedTyposInExpr(LHS);
359       return ExprError();
360     }
361     ExprResult Op = Actions.ActOnBinOp(getCurScope(), LogicalOrLoc,
362                                        tok::pipepipe, LHS.get(), RHS.get());
363     if (!Op.isUsable()) {
364       Actions.CorrectDelayedTyposInExpr(RHS);
365       Actions.CorrectDelayedTyposInExpr(LHS);
366       return ExprError();
367     }
368     LHS = Op;
369   }
370   return LHS;
371 }
372 
373 bool Parser::isNotExpressionStart() {
374   tok::TokenKind K = Tok.getKind();
375   if (K == tok::l_brace || K == tok::r_brace  ||
376       K == tok::kw_for  || K == tok::kw_while ||
377       K == tok::kw_if   || K == tok::kw_else  ||
378       K == tok::kw_goto || K == tok::kw_try)
379     return true;
380   // If this is a decl-specifier, we can't be at the start of an expression.
381   return isKnownToBeDeclarationSpecifier();
382 }
383 
384 bool Parser::isFoldOperator(prec::Level Level) const {
385   return Level > prec::Unknown && Level != prec::Conditional &&
386          Level != prec::Spaceship;
387 }
388 
389 bool Parser::isFoldOperator(tok::TokenKind Kind) const {
390   return isFoldOperator(getBinOpPrecedence(Kind, GreaterThanIsOperator, true));
391 }
392 
393 /// Parse a binary expression that starts with \p LHS and has a
394 /// precedence of at least \p MinPrec.
395 ExprResult
396 Parser::ParseRHSOfBinaryExpression(ExprResult LHS, prec::Level MinPrec) {
397   prec::Level NextTokPrec = getBinOpPrecedence(Tok.getKind(),
398                                                GreaterThanIsOperator,
399                                                getLangOpts().CPlusPlus11);
400   SourceLocation ColonLoc;
401 
402   auto SavedType = PreferredType;
403   while (1) {
404     // Every iteration may rely on a preferred type for the whole expression.
405     PreferredType = SavedType;
406     // If this token has a lower precedence than we are allowed to parse (e.g.
407     // because we are called recursively, or because the token is not a binop),
408     // then we are done!
409     if (NextTokPrec < MinPrec)
410       return LHS;
411 
412     // Consume the operator, saving the operator token for error reporting.
413     Token OpToken = Tok;
414     ConsumeToken();
415 
416     if (OpToken.is(tok::caretcaret)) {
417       return ExprError(Diag(Tok, diag::err_opencl_logical_exclusive_or));
418     }
419 
420     // If we're potentially in a template-id, we may now be able to determine
421     // whether we're actually in one or not.
422     if (OpToken.isOneOf(tok::comma, tok::greater, tok::greatergreater,
423                         tok::greatergreatergreater) &&
424         checkPotentialAngleBracketDelimiter(OpToken))
425       return ExprError();
426 
427     // Bail out when encountering a comma followed by a token which can't
428     // possibly be the start of an expression. For instance:
429     //   int f() { return 1, }
430     // We can't do this before consuming the comma, because
431     // isNotExpressionStart() looks at the token stream.
432     if (OpToken.is(tok::comma) && isNotExpressionStart()) {
433       PP.EnterToken(Tok, /*IsReinject*/true);
434       Tok = OpToken;
435       return LHS;
436     }
437 
438     // If the next token is an ellipsis, then this is a fold-expression. Leave
439     // it alone so we can handle it in the paren expression.
440     if (isFoldOperator(NextTokPrec) && Tok.is(tok::ellipsis)) {
441       // FIXME: We can't check this via lookahead before we consume the token
442       // because that tickles a lexer bug.
443       PP.EnterToken(Tok, /*IsReinject*/true);
444       Tok = OpToken;
445       return LHS;
446     }
447 
448     // In Objective-C++, alternative operator tokens can be used as keyword args
449     // in message expressions. Unconsume the token so that it can reinterpreted
450     // as an identifier in ParseObjCMessageExpressionBody. i.e., we support:
451     //   [foo meth:0 and:0];
452     //   [foo not_eq];
453     if (getLangOpts().ObjC && getLangOpts().CPlusPlus &&
454         Tok.isOneOf(tok::colon, tok::r_square) &&
455         OpToken.getIdentifierInfo() != nullptr) {
456       PP.EnterToken(Tok, /*IsReinject*/true);
457       Tok = OpToken;
458       return LHS;
459     }
460 
461     // Special case handling for the ternary operator.
462     ExprResult TernaryMiddle(true);
463     if (NextTokPrec == prec::Conditional) {
464       if (getLangOpts().CPlusPlus11 && Tok.is(tok::l_brace)) {
465         // Parse a braced-init-list here for error recovery purposes.
466         SourceLocation BraceLoc = Tok.getLocation();
467         TernaryMiddle = ParseBraceInitializer();
468         if (!TernaryMiddle.isInvalid()) {
469           Diag(BraceLoc, diag::err_init_list_bin_op)
470               << /*RHS*/ 1 << PP.getSpelling(OpToken)
471               << Actions.getExprRange(TernaryMiddle.get());
472           TernaryMiddle = ExprError();
473         }
474       } else if (Tok.isNot(tok::colon)) {
475         // Don't parse FOO:BAR as if it were a typo for FOO::BAR.
476         ColonProtectionRAIIObject X(*this);
477 
478         // Handle this production specially:
479         //   logical-OR-expression '?' expression ':' conditional-expression
480         // In particular, the RHS of the '?' is 'expression', not
481         // 'logical-OR-expression' as we might expect.
482         TernaryMiddle = ParseExpression();
483       } else {
484         // Special case handling of "X ? Y : Z" where Y is empty:
485         //   logical-OR-expression '?' ':' conditional-expression   [GNU]
486         TernaryMiddle = nullptr;
487         Diag(Tok, diag::ext_gnu_conditional_expr);
488       }
489 
490       if (TernaryMiddle.isInvalid()) {
491         Actions.CorrectDelayedTyposInExpr(LHS);
492         LHS = ExprError();
493         TernaryMiddle = nullptr;
494       }
495 
496       if (!TryConsumeToken(tok::colon, ColonLoc)) {
497         // Otherwise, we're missing a ':'.  Assume that this was a typo that
498         // the user forgot. If we're not in a macro expansion, we can suggest
499         // a fixit hint. If there were two spaces before the current token,
500         // suggest inserting the colon in between them, otherwise insert ": ".
501         SourceLocation FILoc = Tok.getLocation();
502         const char *FIText = ": ";
503         const SourceManager &SM = PP.getSourceManager();
504         if (FILoc.isFileID() || PP.isAtStartOfMacroExpansion(FILoc, &FILoc)) {
505           assert(FILoc.isFileID());
506           bool IsInvalid = false;
507           const char *SourcePtr =
508             SM.getCharacterData(FILoc.getLocWithOffset(-1), &IsInvalid);
509           if (!IsInvalid && *SourcePtr == ' ') {
510             SourcePtr =
511               SM.getCharacterData(FILoc.getLocWithOffset(-2), &IsInvalid);
512             if (!IsInvalid && *SourcePtr == ' ') {
513               FILoc = FILoc.getLocWithOffset(-1);
514               FIText = ":";
515             }
516           }
517         }
518 
519         Diag(Tok, diag::err_expected)
520             << tok::colon << FixItHint::CreateInsertion(FILoc, FIText);
521         Diag(OpToken, diag::note_matching) << tok::question;
522         ColonLoc = Tok.getLocation();
523       }
524     }
525 
526     PreferredType.enterBinary(Actions, Tok.getLocation(), LHS.get(),
527                               OpToken.getKind());
528     // Parse another leaf here for the RHS of the operator.
529     // ParseCastExpression works here because all RHS expressions in C have it
530     // as a prefix, at least. However, in C++, an assignment-expression could
531     // be a throw-expression, which is not a valid cast-expression.
532     // Therefore we need some special-casing here.
533     // Also note that the third operand of the conditional operator is
534     // an assignment-expression in C++, and in C++11, we can have a
535     // braced-init-list on the RHS of an assignment. For better diagnostics,
536     // parse as if we were allowed braced-init-lists everywhere, and check that
537     // they only appear on the RHS of assignments later.
538     ExprResult RHS;
539     bool RHSIsInitList = false;
540     if (getLangOpts().CPlusPlus11 && Tok.is(tok::l_brace)) {
541       RHS = ParseBraceInitializer();
542       RHSIsInitList = true;
543     } else if (getLangOpts().CPlusPlus && NextTokPrec <= prec::Conditional)
544       RHS = ParseAssignmentExpression();
545     else
546       RHS = ParseCastExpression(AnyCastExpr);
547 
548     if (RHS.isInvalid()) {
549       // FIXME: Errors generated by the delayed typo correction should be
550       // printed before errors from parsing the RHS, not after.
551       Actions.CorrectDelayedTyposInExpr(LHS);
552       if (TernaryMiddle.isUsable())
553         TernaryMiddle = Actions.CorrectDelayedTyposInExpr(TernaryMiddle);
554       LHS = ExprError();
555     }
556 
557     // Remember the precedence of this operator and get the precedence of the
558     // operator immediately to the right of the RHS.
559     prec::Level ThisPrec = NextTokPrec;
560     NextTokPrec = getBinOpPrecedence(Tok.getKind(), GreaterThanIsOperator,
561                                      getLangOpts().CPlusPlus11);
562 
563     // Assignment and conditional expressions are right-associative.
564     bool isRightAssoc = ThisPrec == prec::Conditional ||
565                         ThisPrec == prec::Assignment;
566 
567     // Get the precedence of the operator to the right of the RHS.  If it binds
568     // more tightly with RHS than we do, evaluate it completely first.
569     if (ThisPrec < NextTokPrec ||
570         (ThisPrec == NextTokPrec && isRightAssoc)) {
571       if (!RHS.isInvalid() && RHSIsInitList) {
572         Diag(Tok, diag::err_init_list_bin_op)
573           << /*LHS*/0 << PP.getSpelling(Tok) << Actions.getExprRange(RHS.get());
574         RHS = ExprError();
575       }
576       // If this is left-associative, only parse things on the RHS that bind
577       // more tightly than the current operator.  If it is left-associative, it
578       // is okay, to bind exactly as tightly.  For example, compile A=B=C=D as
579       // A=(B=(C=D)), where each paren is a level of recursion here.
580       // The function takes ownership of the RHS.
581       RHS = ParseRHSOfBinaryExpression(RHS,
582                             static_cast<prec::Level>(ThisPrec + !isRightAssoc));
583       RHSIsInitList = false;
584 
585       if (RHS.isInvalid()) {
586         // FIXME: Errors generated by the delayed typo correction should be
587         // printed before errors from ParseRHSOfBinaryExpression, not after.
588         Actions.CorrectDelayedTyposInExpr(LHS);
589         if (TernaryMiddle.isUsable())
590           TernaryMiddle = Actions.CorrectDelayedTyposInExpr(TernaryMiddle);
591         LHS = ExprError();
592       }
593 
594       NextTokPrec = getBinOpPrecedence(Tok.getKind(), GreaterThanIsOperator,
595                                        getLangOpts().CPlusPlus11);
596     }
597 
598     if (!RHS.isInvalid() && RHSIsInitList) {
599       if (ThisPrec == prec::Assignment) {
600         Diag(OpToken, diag::warn_cxx98_compat_generalized_initializer_lists)
601           << Actions.getExprRange(RHS.get());
602       } else if (ColonLoc.isValid()) {
603         Diag(ColonLoc, diag::err_init_list_bin_op)
604           << /*RHS*/1 << ":"
605           << Actions.getExprRange(RHS.get());
606         LHS = ExprError();
607       } else {
608         Diag(OpToken, diag::err_init_list_bin_op)
609           << /*RHS*/1 << PP.getSpelling(OpToken)
610           << Actions.getExprRange(RHS.get());
611         LHS = ExprError();
612       }
613     }
614 
615     ExprResult OrigLHS = LHS;
616     if (!LHS.isInvalid()) {
617       // Combine the LHS and RHS into the LHS (e.g. build AST).
618       if (TernaryMiddle.isInvalid()) {
619         // If we're using '>>' as an operator within a template
620         // argument list (in C++98), suggest the addition of
621         // parentheses so that the code remains well-formed in C++0x.
622         if (!GreaterThanIsOperator && OpToken.is(tok::greatergreater))
623           SuggestParentheses(OpToken.getLocation(),
624                              diag::warn_cxx11_right_shift_in_template_arg,
625                          SourceRange(Actions.getExprRange(LHS.get()).getBegin(),
626                                      Actions.getExprRange(RHS.get()).getEnd()));
627 
628         ExprResult BinOp =
629             Actions.ActOnBinOp(getCurScope(), OpToken.getLocation(),
630                                OpToken.getKind(), LHS.get(), RHS.get());
631         if (BinOp.isInvalid())
632           BinOp = Actions.CreateRecoveryExpr(LHS.get()->getBeginLoc(),
633                                              RHS.get()->getEndLoc(),
634                                              {LHS.get(), RHS.get()});
635 
636         LHS = BinOp;
637       } else {
638         ExprResult CondOp = Actions.ActOnConditionalOp(
639             OpToken.getLocation(), ColonLoc, LHS.get(), TernaryMiddle.get(),
640             RHS.get());
641         if (CondOp.isInvalid()) {
642           std::vector<clang::Expr *> Args;
643           // TernaryMiddle can be null for the GNU conditional expr extension.
644           if (TernaryMiddle.get())
645             Args = {LHS.get(), TernaryMiddle.get(), RHS.get()};
646           else
647             Args = {LHS.get(), RHS.get()};
648           CondOp = Actions.CreateRecoveryExpr(LHS.get()->getBeginLoc(),
649                                               RHS.get()->getEndLoc(), Args);
650         }
651 
652         LHS = CondOp;
653       }
654       // In this case, ActOnBinOp or ActOnConditionalOp performed the
655       // CorrectDelayedTyposInExpr check.
656       if (!getLangOpts().CPlusPlus)
657         continue;
658     }
659 
660     // Ensure potential typos aren't left undiagnosed.
661     if (LHS.isInvalid()) {
662       Actions.CorrectDelayedTyposInExpr(OrigLHS);
663       Actions.CorrectDelayedTyposInExpr(TernaryMiddle);
664       Actions.CorrectDelayedTyposInExpr(RHS);
665     }
666   }
667 }
668 
669 /// Parse a cast-expression, unary-expression or primary-expression, based
670 /// on \p ExprType.
671 ///
672 /// \p isAddressOfOperand exists because an id-expression that is the
673 /// operand of address-of gets special treatment due to member pointers.
674 ///
675 ExprResult Parser::ParseCastExpression(CastParseKind ParseKind,
676                                        bool isAddressOfOperand,
677                                        TypeCastState isTypeCast,
678                                        bool isVectorLiteral,
679                                        bool *NotPrimaryExpression) {
680   bool NotCastExpr;
681   ExprResult Res = ParseCastExpression(ParseKind,
682                                        isAddressOfOperand,
683                                        NotCastExpr,
684                                        isTypeCast,
685                                        isVectorLiteral,
686                                        NotPrimaryExpression);
687   if (NotCastExpr)
688     Diag(Tok, diag::err_expected_expression);
689   return Res;
690 }
691 
692 namespace {
693 class CastExpressionIdValidator final : public CorrectionCandidateCallback {
694  public:
695   CastExpressionIdValidator(Token Next, bool AllowTypes, bool AllowNonTypes)
696       : NextToken(Next), AllowNonTypes(AllowNonTypes) {
697     WantTypeSpecifiers = WantFunctionLikeCasts = AllowTypes;
698   }
699 
700   bool ValidateCandidate(const TypoCorrection &candidate) override {
701     NamedDecl *ND = candidate.getCorrectionDecl();
702     if (!ND)
703       return candidate.isKeyword();
704 
705     if (isa<TypeDecl>(ND))
706       return WantTypeSpecifiers;
707 
708     if (!AllowNonTypes || !CorrectionCandidateCallback::ValidateCandidate(candidate))
709       return false;
710 
711     if (!NextToken.isOneOf(tok::equal, tok::arrow, tok::period))
712       return true;
713 
714     for (auto *C : candidate) {
715       NamedDecl *ND = C->getUnderlyingDecl();
716       if (isa<ValueDecl>(ND) && !isa<FunctionDecl>(ND))
717         return true;
718     }
719     return false;
720   }
721 
722   std::unique_ptr<CorrectionCandidateCallback> clone() override {
723     return std::make_unique<CastExpressionIdValidator>(*this);
724   }
725 
726  private:
727   Token NextToken;
728   bool AllowNonTypes;
729 };
730 }
731 
732 /// Parse a cast-expression, or, if \pisUnaryExpression is true, parse
733 /// a unary-expression.
734 ///
735 /// \p isAddressOfOperand exists because an id-expression that is the operand
736 /// of address-of gets special treatment due to member pointers. NotCastExpr
737 /// is set to true if the token is not the start of a cast-expression, and no
738 /// diagnostic is emitted in this case and no tokens are consumed.
739 ///
740 /// \verbatim
741 ///       cast-expression: [C99 6.5.4]
742 ///         unary-expression
743 ///         '(' type-name ')' cast-expression
744 ///
745 ///       unary-expression:  [C99 6.5.3]
746 ///         postfix-expression
747 ///         '++' unary-expression
748 ///         '--' unary-expression
749 /// [Coro]  'co_await' cast-expression
750 ///         unary-operator cast-expression
751 ///         'sizeof' unary-expression
752 ///         'sizeof' '(' type-name ')'
753 /// [C++11] 'sizeof' '...' '(' identifier ')'
754 /// [GNU]   '__alignof' unary-expression
755 /// [GNU]   '__alignof' '(' type-name ')'
756 /// [C11]   '_Alignof' '(' type-name ')'
757 /// [C++11] 'alignof' '(' type-id ')'
758 /// [GNU]   '&&' identifier
759 /// [C++11] 'noexcept' '(' expression ')' [C++11 5.3.7]
760 /// [C++]   new-expression
761 /// [C++]   delete-expression
762 ///
763 ///       unary-operator: one of
764 ///         '&'  '*'  '+'  '-'  '~'  '!'
765 /// [GNU]   '__extension__'  '__real'  '__imag'
766 ///
767 ///       primary-expression: [C99 6.5.1]
768 /// [C99]   identifier
769 /// [C++]   id-expression
770 ///         constant
771 ///         string-literal
772 /// [C++]   boolean-literal  [C++ 2.13.5]
773 /// [C++11] 'nullptr'        [C++11 2.14.7]
774 /// [C++11] user-defined-literal
775 ///         '(' expression ')'
776 /// [C11]   generic-selection
777 /// [C++2a] requires-expression
778 ///         '__func__'        [C99 6.4.2.2]
779 /// [GNU]   '__FUNCTION__'
780 /// [MS]    '__FUNCDNAME__'
781 /// [MS]    'L__FUNCTION__'
782 /// [MS]    '__FUNCSIG__'
783 /// [MS]    'L__FUNCSIG__'
784 /// [GNU]   '__PRETTY_FUNCTION__'
785 /// [GNU]   '(' compound-statement ')'
786 /// [GNU]   '__builtin_va_arg' '(' assignment-expression ',' type-name ')'
787 /// [GNU]   '__builtin_offsetof' '(' type-name ',' offsetof-member-designator')'
788 /// [GNU]   '__builtin_choose_expr' '(' assign-expr ',' assign-expr ','
789 ///                                     assign-expr ')'
790 /// [GNU]   '__builtin_FILE' '(' ')'
791 /// [GNU]   '__builtin_FUNCTION' '(' ')'
792 /// [GNU]   '__builtin_LINE' '(' ')'
793 /// [CLANG] '__builtin_COLUMN' '(' ')'
794 /// [GNU]   '__builtin_types_compatible_p' '(' type-name ',' type-name ')'
795 /// [GNU]   '__null'
796 /// [OBJC]  '[' objc-message-expr ']'
797 /// [OBJC]  '\@selector' '(' objc-selector-arg ')'
798 /// [OBJC]  '\@protocol' '(' identifier ')'
799 /// [OBJC]  '\@encode' '(' type-name ')'
800 /// [OBJC]  objc-string-literal
801 /// [C++]   simple-type-specifier '(' expression-list[opt] ')'      [C++ 5.2.3]
802 /// [C++11] simple-type-specifier braced-init-list                  [C++11 5.2.3]
803 /// [C++]   typename-specifier '(' expression-list[opt] ')'         [C++ 5.2.3]
804 /// [C++11] typename-specifier braced-init-list                     [C++11 5.2.3]
805 /// [C++]   'const_cast' '<' type-name '>' '(' expression ')'       [C++ 5.2p1]
806 /// [C++]   'dynamic_cast' '<' type-name '>' '(' expression ')'     [C++ 5.2p1]
807 /// [C++]   'reinterpret_cast' '<' type-name '>' '(' expression ')' [C++ 5.2p1]
808 /// [C++]   'static_cast' '<' type-name '>' '(' expression ')'      [C++ 5.2p1]
809 /// [C++]   'typeid' '(' expression ')'                             [C++ 5.2p1]
810 /// [C++]   'typeid' '(' type-id ')'                                [C++ 5.2p1]
811 /// [C++]   'this'          [C++ 9.3.2]
812 /// [G++]   unary-type-trait '(' type-id ')'
813 /// [G++]   binary-type-trait '(' type-id ',' type-id ')'           [TODO]
814 /// [EMBT]  array-type-trait '(' type-id ',' integer ')'
815 /// [clang] '^' block-literal
816 ///
817 ///       constant: [C99 6.4.4]
818 ///         integer-constant
819 ///         floating-constant
820 ///         enumeration-constant -> identifier
821 ///         character-constant
822 ///
823 ///       id-expression: [C++ 5.1]
824 ///                   unqualified-id
825 ///                   qualified-id
826 ///
827 ///       unqualified-id: [C++ 5.1]
828 ///                   identifier
829 ///                   operator-function-id
830 ///                   conversion-function-id
831 ///                   '~' class-name
832 ///                   template-id
833 ///
834 ///       new-expression: [C++ 5.3.4]
835 ///                   '::'[opt] 'new' new-placement[opt] new-type-id
836 ///                                     new-initializer[opt]
837 ///                   '::'[opt] 'new' new-placement[opt] '(' type-id ')'
838 ///                                     new-initializer[opt]
839 ///
840 ///       delete-expression: [C++ 5.3.5]
841 ///                   '::'[opt] 'delete' cast-expression
842 ///                   '::'[opt] 'delete' '[' ']' cast-expression
843 ///
844 /// [GNU/Embarcadero] unary-type-trait:
845 ///                   '__is_arithmetic'
846 ///                   '__is_floating_point'
847 ///                   '__is_integral'
848 ///                   '__is_lvalue_expr'
849 ///                   '__is_rvalue_expr'
850 ///                   '__is_complete_type'
851 ///                   '__is_void'
852 ///                   '__is_array'
853 ///                   '__is_function'
854 ///                   '__is_reference'
855 ///                   '__is_lvalue_reference'
856 ///                   '__is_rvalue_reference'
857 ///                   '__is_fundamental'
858 ///                   '__is_object'
859 ///                   '__is_scalar'
860 ///                   '__is_compound'
861 ///                   '__is_pointer'
862 ///                   '__is_member_object_pointer'
863 ///                   '__is_member_function_pointer'
864 ///                   '__is_member_pointer'
865 ///                   '__is_const'
866 ///                   '__is_volatile'
867 ///                   '__is_trivial'
868 ///                   '__is_standard_layout'
869 ///                   '__is_signed'
870 ///                   '__is_unsigned'
871 ///
872 /// [GNU] unary-type-trait:
873 ///                   '__has_nothrow_assign'
874 ///                   '__has_nothrow_copy'
875 ///                   '__has_nothrow_constructor'
876 ///                   '__has_trivial_assign'                  [TODO]
877 ///                   '__has_trivial_copy'                    [TODO]
878 ///                   '__has_trivial_constructor'
879 ///                   '__has_trivial_destructor'
880 ///                   '__has_virtual_destructor'
881 ///                   '__is_abstract'                         [TODO]
882 ///                   '__is_class'
883 ///                   '__is_empty'                            [TODO]
884 ///                   '__is_enum'
885 ///                   '__is_final'
886 ///                   '__is_pod'
887 ///                   '__is_polymorphic'
888 ///                   '__is_sealed'                           [MS]
889 ///                   '__is_trivial'
890 ///                   '__is_union'
891 ///                   '__has_unique_object_representations'
892 ///
893 /// [Clang] unary-type-trait:
894 ///                   '__is_aggregate'
895 ///                   '__trivially_copyable'
896 ///
897 ///       binary-type-trait:
898 /// [GNU]             '__is_base_of'
899 /// [MS]              '__is_convertible_to'
900 ///                   '__is_convertible'
901 ///                   '__is_same'
902 ///
903 /// [Embarcadero] array-type-trait:
904 ///                   '__array_rank'
905 ///                   '__array_extent'
906 ///
907 /// [Embarcadero] expression-trait:
908 ///                   '__is_lvalue_expr'
909 ///                   '__is_rvalue_expr'
910 /// \endverbatim
911 ///
912 ExprResult Parser::ParseCastExpression(CastParseKind ParseKind,
913                                        bool isAddressOfOperand,
914                                        bool &NotCastExpr,
915                                        TypeCastState isTypeCast,
916                                        bool isVectorLiteral,
917                                        bool *NotPrimaryExpression) {
918   ExprResult Res;
919   tok::TokenKind SavedKind = Tok.getKind();
920   auto SavedType = PreferredType;
921   NotCastExpr = false;
922 
923   // Are postfix-expression suffix operators permitted after this
924   // cast-expression? If not, and we find some, we'll parse them anyway and
925   // diagnose them.
926   bool AllowSuffix = true;
927 
928   // This handles all of cast-expression, unary-expression, postfix-expression,
929   // and primary-expression.  We handle them together like this for efficiency
930   // and to simplify handling of an expression starting with a '(' token: which
931   // may be one of a parenthesized expression, cast-expression, compound literal
932   // expression, or statement expression.
933   //
934   // If the parsed tokens consist of a primary-expression, the cases below
935   // break out of the switch;  at the end we call ParsePostfixExpressionSuffix
936   // to handle the postfix expression suffixes.  Cases that cannot be followed
937   // by postfix exprs should set AllowSuffix to false.
938   switch (SavedKind) {
939   case tok::l_paren: {
940     // If this expression is limited to being a unary-expression, the paren can
941     // not start a cast expression.
942     ParenParseOption ParenExprType;
943     switch (ParseKind) {
944       case CastParseKind::UnaryExprOnly:
945         if (!getLangOpts().CPlusPlus)
946           ParenExprType = CompoundLiteral;
947         LLVM_FALLTHROUGH;
948       case CastParseKind::AnyCastExpr:
949         ParenExprType = ParenParseOption::CastExpr;
950         break;
951       case CastParseKind::PrimaryExprOnly:
952         ParenExprType = FoldExpr;
953         break;
954     }
955     ParsedType CastTy;
956     SourceLocation RParenLoc;
957     Res = ParseParenExpression(ParenExprType, false/*stopIfCastExr*/,
958                                isTypeCast == IsTypeCast, CastTy, RParenLoc);
959 
960     // FIXME: What should we do if a vector literal is followed by a
961     // postfix-expression suffix? Usually postfix operators are permitted on
962     // literals.
963     if (isVectorLiteral)
964       return Res;
965 
966     switch (ParenExprType) {
967     case SimpleExpr:   break;    // Nothing else to do.
968     case CompoundStmt: break;  // Nothing else to do.
969     case CompoundLiteral:
970       // We parsed '(' type-name ')' '{' ... '}'.  If any suffixes of
971       // postfix-expression exist, parse them now.
972       break;
973     case CastExpr:
974       // We have parsed the cast-expression and no postfix-expr pieces are
975       // following.
976       return Res;
977     case FoldExpr:
978       // We only parsed a fold-expression. There might be postfix-expr pieces
979       // afterwards; parse them now.
980       break;
981     }
982 
983     break;
984   }
985 
986     // primary-expression
987   case tok::numeric_constant:
988     // constant: integer-constant
989     // constant: floating-constant
990 
991     Res = Actions.ActOnNumericConstant(Tok, /*UDLScope*/getCurScope());
992     ConsumeToken();
993     break;
994 
995   case tok::kw_true:
996   case tok::kw_false:
997     Res = ParseCXXBoolLiteral();
998     break;
999 
1000   case tok::kw___objc_yes:
1001   case tok::kw___objc_no:
1002     Res = ParseObjCBoolLiteral();
1003     break;
1004 
1005   case tok::kw_nullptr:
1006     Diag(Tok, diag::warn_cxx98_compat_nullptr);
1007     Res = Actions.ActOnCXXNullPtrLiteral(ConsumeToken());
1008     break;
1009 
1010   case tok::annot_primary_expr:
1011   case tok::annot_overload_set:
1012     Res = getExprAnnotation(Tok);
1013     if (!Res.isInvalid() && Tok.getKind() == tok::annot_overload_set)
1014       Res = Actions.ActOnNameClassifiedAsOverloadSet(getCurScope(), Res.get());
1015     ConsumeAnnotationToken();
1016     if (!Res.isInvalid() && Tok.is(tok::less))
1017       checkPotentialAngleBracket(Res);
1018     break;
1019 
1020   case tok::annot_non_type:
1021   case tok::annot_non_type_dependent:
1022   case tok::annot_non_type_undeclared: {
1023     CXXScopeSpec SS;
1024     Token Replacement;
1025     Res = tryParseCXXIdExpression(SS, isAddressOfOperand, Replacement);
1026     assert(!Res.isUnset() &&
1027            "should not perform typo correction on annotation token");
1028     break;
1029   }
1030 
1031   case tok::kw___super:
1032   case tok::kw_decltype:
1033     // Annotate the token and tail recurse.
1034     if (TryAnnotateTypeOrScopeToken())
1035       return ExprError();
1036     assert(Tok.isNot(tok::kw_decltype) && Tok.isNot(tok::kw___super));
1037     return ParseCastExpression(ParseKind, isAddressOfOperand, isTypeCast,
1038                                isVectorLiteral, NotPrimaryExpression);
1039 
1040   case tok::identifier: {      // primary-expression: identifier
1041                                // unqualified-id: identifier
1042                                // constant: enumeration-constant
1043     // Turn a potentially qualified name into a annot_typename or
1044     // annot_cxxscope if it would be valid.  This handles things like x::y, etc.
1045     if (getLangOpts().CPlusPlus) {
1046       // Avoid the unnecessary parse-time lookup in the common case
1047       // where the syntax forbids a type.
1048       const Token &Next = NextToken();
1049 
1050       // If this identifier was reverted from a token ID, and the next token
1051       // is a parenthesis, this is likely to be a use of a type trait. Check
1052       // those tokens.
1053       if (Next.is(tok::l_paren) &&
1054           Tok.is(tok::identifier) &&
1055           Tok.getIdentifierInfo()->hasRevertedTokenIDToIdentifier()) {
1056         IdentifierInfo *II = Tok.getIdentifierInfo();
1057         // Build up the mapping of revertible type traits, for future use.
1058         if (RevertibleTypeTraits.empty()) {
1059 #define RTT_JOIN(X,Y) X##Y
1060 #define REVERTIBLE_TYPE_TRAIT(Name)                         \
1061           RevertibleTypeTraits[PP.getIdentifierInfo(#Name)] \
1062             = RTT_JOIN(tok::kw_,Name)
1063 
1064           REVERTIBLE_TYPE_TRAIT(__is_abstract);
1065           REVERTIBLE_TYPE_TRAIT(__is_aggregate);
1066           REVERTIBLE_TYPE_TRAIT(__is_arithmetic);
1067           REVERTIBLE_TYPE_TRAIT(__is_array);
1068           REVERTIBLE_TYPE_TRAIT(__is_assignable);
1069           REVERTIBLE_TYPE_TRAIT(__is_base_of);
1070           REVERTIBLE_TYPE_TRAIT(__is_class);
1071           REVERTIBLE_TYPE_TRAIT(__is_complete_type);
1072           REVERTIBLE_TYPE_TRAIT(__is_compound);
1073           REVERTIBLE_TYPE_TRAIT(__is_const);
1074           REVERTIBLE_TYPE_TRAIT(__is_constructible);
1075           REVERTIBLE_TYPE_TRAIT(__is_convertible);
1076           REVERTIBLE_TYPE_TRAIT(__is_convertible_to);
1077           REVERTIBLE_TYPE_TRAIT(__is_destructible);
1078           REVERTIBLE_TYPE_TRAIT(__is_empty);
1079           REVERTIBLE_TYPE_TRAIT(__is_enum);
1080           REVERTIBLE_TYPE_TRAIT(__is_floating_point);
1081           REVERTIBLE_TYPE_TRAIT(__is_final);
1082           REVERTIBLE_TYPE_TRAIT(__is_function);
1083           REVERTIBLE_TYPE_TRAIT(__is_fundamental);
1084           REVERTIBLE_TYPE_TRAIT(__is_integral);
1085           REVERTIBLE_TYPE_TRAIT(__is_interface_class);
1086           REVERTIBLE_TYPE_TRAIT(__is_literal);
1087           REVERTIBLE_TYPE_TRAIT(__is_lvalue_expr);
1088           REVERTIBLE_TYPE_TRAIT(__is_lvalue_reference);
1089           REVERTIBLE_TYPE_TRAIT(__is_member_function_pointer);
1090           REVERTIBLE_TYPE_TRAIT(__is_member_object_pointer);
1091           REVERTIBLE_TYPE_TRAIT(__is_member_pointer);
1092           REVERTIBLE_TYPE_TRAIT(__is_nothrow_assignable);
1093           REVERTIBLE_TYPE_TRAIT(__is_nothrow_constructible);
1094           REVERTIBLE_TYPE_TRAIT(__is_nothrow_destructible);
1095           REVERTIBLE_TYPE_TRAIT(__is_object);
1096           REVERTIBLE_TYPE_TRAIT(__is_pod);
1097           REVERTIBLE_TYPE_TRAIT(__is_pointer);
1098           REVERTIBLE_TYPE_TRAIT(__is_polymorphic);
1099           REVERTIBLE_TYPE_TRAIT(__is_reference);
1100           REVERTIBLE_TYPE_TRAIT(__is_rvalue_expr);
1101           REVERTIBLE_TYPE_TRAIT(__is_rvalue_reference);
1102           REVERTIBLE_TYPE_TRAIT(__is_same);
1103           REVERTIBLE_TYPE_TRAIT(__is_scalar);
1104           REVERTIBLE_TYPE_TRAIT(__is_sealed);
1105           REVERTIBLE_TYPE_TRAIT(__is_signed);
1106           REVERTIBLE_TYPE_TRAIT(__is_standard_layout);
1107           REVERTIBLE_TYPE_TRAIT(__is_trivial);
1108           REVERTIBLE_TYPE_TRAIT(__is_trivially_assignable);
1109           REVERTIBLE_TYPE_TRAIT(__is_trivially_constructible);
1110           REVERTIBLE_TYPE_TRAIT(__is_trivially_copyable);
1111           REVERTIBLE_TYPE_TRAIT(__is_union);
1112           REVERTIBLE_TYPE_TRAIT(__is_unsigned);
1113           REVERTIBLE_TYPE_TRAIT(__is_void);
1114           REVERTIBLE_TYPE_TRAIT(__is_volatile);
1115 #undef REVERTIBLE_TYPE_TRAIT
1116 #undef RTT_JOIN
1117         }
1118 
1119         // If we find that this is in fact the name of a type trait,
1120         // update the token kind in place and parse again to treat it as
1121         // the appropriate kind of type trait.
1122         llvm::SmallDenseMap<IdentifierInfo *, tok::TokenKind>::iterator Known
1123           = RevertibleTypeTraits.find(II);
1124         if (Known != RevertibleTypeTraits.end()) {
1125           Tok.setKind(Known->second);
1126           return ParseCastExpression(ParseKind, isAddressOfOperand,
1127                                      NotCastExpr, isTypeCast,
1128                                      isVectorLiteral, NotPrimaryExpression);
1129         }
1130       }
1131 
1132       if ((!ColonIsSacred && Next.is(tok::colon)) ||
1133           Next.isOneOf(tok::coloncolon, tok::less, tok::l_paren,
1134                        tok::l_brace)) {
1135         // If TryAnnotateTypeOrScopeToken annotates the token, tail recurse.
1136         if (TryAnnotateTypeOrScopeToken())
1137           return ExprError();
1138         if (!Tok.is(tok::identifier))
1139           return ParseCastExpression(ParseKind, isAddressOfOperand,
1140                                      NotCastExpr, isTypeCast,
1141                                      isVectorLiteral,
1142                                      NotPrimaryExpression);
1143       }
1144     }
1145 
1146     // Consume the identifier so that we can see if it is followed by a '(' or
1147     // '.'.
1148     IdentifierInfo &II = *Tok.getIdentifierInfo();
1149     SourceLocation ILoc = ConsumeToken();
1150 
1151     // Support 'Class.property' and 'super.property' notation.
1152     if (getLangOpts().ObjC && Tok.is(tok::period) &&
1153         (Actions.getTypeName(II, ILoc, getCurScope()) ||
1154          // Allow the base to be 'super' if in an objc-method.
1155          (&II == Ident_super && getCurScope()->isInObjcMethodScope()))) {
1156       ConsumeToken();
1157 
1158       if (Tok.is(tok::code_completion) && &II != Ident_super) {
1159         Actions.CodeCompleteObjCClassPropertyRefExpr(
1160             getCurScope(), II, ILoc, ExprStatementTokLoc == ILoc);
1161         cutOffParsing();
1162         return ExprError();
1163       }
1164       // Allow either an identifier or the keyword 'class' (in C++).
1165       if (Tok.isNot(tok::identifier) &&
1166           !(getLangOpts().CPlusPlus && Tok.is(tok::kw_class))) {
1167         Diag(Tok, diag::err_expected_property_name);
1168         return ExprError();
1169       }
1170       IdentifierInfo &PropertyName = *Tok.getIdentifierInfo();
1171       SourceLocation PropertyLoc = ConsumeToken();
1172 
1173       Res = Actions.ActOnClassPropertyRefExpr(II, PropertyName,
1174                                               ILoc, PropertyLoc);
1175       break;
1176     }
1177 
1178     // In an Objective-C method, if we have "super" followed by an identifier,
1179     // the token sequence is ill-formed. However, if there's a ':' or ']' after
1180     // that identifier, this is probably a message send with a missing open
1181     // bracket. Treat it as such.
1182     if (getLangOpts().ObjC && &II == Ident_super && !InMessageExpression &&
1183         getCurScope()->isInObjcMethodScope() &&
1184         ((Tok.is(tok::identifier) &&
1185          (NextToken().is(tok::colon) || NextToken().is(tok::r_square))) ||
1186          Tok.is(tok::code_completion))) {
1187       Res = ParseObjCMessageExpressionBody(SourceLocation(), ILoc, nullptr,
1188                                            nullptr);
1189       break;
1190     }
1191 
1192     // If we have an Objective-C class name followed by an identifier
1193     // and either ':' or ']', this is an Objective-C class message
1194     // send that's missing the opening '['. Recovery
1195     // appropriately. Also take this path if we're performing code
1196     // completion after an Objective-C class name.
1197     if (getLangOpts().ObjC &&
1198         ((Tok.is(tok::identifier) && !InMessageExpression) ||
1199          Tok.is(tok::code_completion))) {
1200       const Token& Next = NextToken();
1201       if (Tok.is(tok::code_completion) ||
1202           Next.is(tok::colon) || Next.is(tok::r_square))
1203         if (ParsedType Typ = Actions.getTypeName(II, ILoc, getCurScope()))
1204           if (Typ.get()->isObjCObjectOrInterfaceType()) {
1205             // Fake up a Declarator to use with ActOnTypeName.
1206             DeclSpec DS(AttrFactory);
1207             DS.SetRangeStart(ILoc);
1208             DS.SetRangeEnd(ILoc);
1209             const char *PrevSpec = nullptr;
1210             unsigned DiagID;
1211             DS.SetTypeSpecType(TST_typename, ILoc, PrevSpec, DiagID, Typ,
1212                                Actions.getASTContext().getPrintingPolicy());
1213 
1214             Declarator DeclaratorInfo(DS, DeclaratorContext::TypeName);
1215             TypeResult Ty = Actions.ActOnTypeName(getCurScope(),
1216                                                   DeclaratorInfo);
1217             if (Ty.isInvalid())
1218               break;
1219 
1220             Res = ParseObjCMessageExpressionBody(SourceLocation(),
1221                                                  SourceLocation(),
1222                                                  Ty.get(), nullptr);
1223             break;
1224           }
1225     }
1226 
1227     // Make sure to pass down the right value for isAddressOfOperand.
1228     if (isAddressOfOperand && isPostfixExpressionSuffixStart())
1229       isAddressOfOperand = false;
1230 
1231     // Function designators are allowed to be undeclared (C99 6.5.1p2), so we
1232     // need to know whether or not this identifier is a function designator or
1233     // not.
1234     UnqualifiedId Name;
1235     CXXScopeSpec ScopeSpec;
1236     SourceLocation TemplateKWLoc;
1237     Token Replacement;
1238     CastExpressionIdValidator Validator(
1239         /*Next=*/Tok,
1240         /*AllowTypes=*/isTypeCast != NotTypeCast,
1241         /*AllowNonTypes=*/isTypeCast != IsTypeCast);
1242     Validator.IsAddressOfOperand = isAddressOfOperand;
1243     if (Tok.isOneOf(tok::periodstar, tok::arrowstar)) {
1244       Validator.WantExpressionKeywords = false;
1245       Validator.WantRemainingKeywords = false;
1246     } else {
1247       Validator.WantRemainingKeywords = Tok.isNot(tok::r_paren);
1248     }
1249     Name.setIdentifier(&II, ILoc);
1250     Res = Actions.ActOnIdExpression(
1251         getCurScope(), ScopeSpec, TemplateKWLoc, Name, Tok.is(tok::l_paren),
1252         isAddressOfOperand, &Validator,
1253         /*IsInlineAsmIdentifier=*/false,
1254         Tok.is(tok::r_paren) ? nullptr : &Replacement);
1255     if (!Res.isInvalid() && Res.isUnset()) {
1256       UnconsumeToken(Replacement);
1257       return ParseCastExpression(ParseKind, isAddressOfOperand,
1258                                  NotCastExpr, isTypeCast,
1259                                  /*isVectorLiteral=*/false,
1260                                  NotPrimaryExpression);
1261     }
1262     if (!Res.isInvalid() && Tok.is(tok::less))
1263       checkPotentialAngleBracket(Res);
1264     break;
1265   }
1266   case tok::char_constant:     // constant: character-constant
1267   case tok::wide_char_constant:
1268   case tok::utf8_char_constant:
1269   case tok::utf16_char_constant:
1270   case tok::utf32_char_constant:
1271     Res = Actions.ActOnCharacterConstant(Tok, /*UDLScope*/getCurScope());
1272     ConsumeToken();
1273     break;
1274   case tok::kw___func__:       // primary-expression: __func__ [C99 6.4.2.2]
1275   case tok::kw___FUNCTION__:   // primary-expression: __FUNCTION__ [GNU]
1276   case tok::kw___FUNCDNAME__:   // primary-expression: __FUNCDNAME__ [MS]
1277   case tok::kw___FUNCSIG__:     // primary-expression: __FUNCSIG__ [MS]
1278   case tok::kw_L__FUNCTION__:   // primary-expression: L__FUNCTION__ [MS]
1279   case tok::kw_L__FUNCSIG__:    // primary-expression: L__FUNCSIG__ [MS]
1280   case tok::kw___PRETTY_FUNCTION__:  // primary-expression: __P..Y_F..N__ [GNU]
1281     Res = Actions.ActOnPredefinedExpr(Tok.getLocation(), SavedKind);
1282     ConsumeToken();
1283     break;
1284   case tok::string_literal:    // primary-expression: string-literal
1285   case tok::wide_string_literal:
1286   case tok::utf8_string_literal:
1287   case tok::utf16_string_literal:
1288   case tok::utf32_string_literal:
1289     Res = ParseStringLiteralExpression(true);
1290     break;
1291   case tok::kw__Generic:   // primary-expression: generic-selection [C11 6.5.1]
1292     Res = ParseGenericSelectionExpression();
1293     break;
1294   case tok::kw___builtin_available:
1295     Res = ParseAvailabilityCheckExpr(Tok.getLocation());
1296     break;
1297   case tok::kw___builtin_va_arg:
1298   case tok::kw___builtin_offsetof:
1299   case tok::kw___builtin_choose_expr:
1300   case tok::kw___builtin_astype: // primary-expression: [OCL] as_type()
1301   case tok::kw___builtin_convertvector:
1302   case tok::kw___builtin_COLUMN:
1303   case tok::kw___builtin_FILE:
1304   case tok::kw___builtin_FUNCTION:
1305   case tok::kw___builtin_LINE:
1306     if (NotPrimaryExpression)
1307       *NotPrimaryExpression = true;
1308     // This parses the complete suffix; we can return early.
1309     return ParseBuiltinPrimaryExpression();
1310   case tok::kw___null:
1311     Res = Actions.ActOnGNUNullExpr(ConsumeToken());
1312     break;
1313 
1314   case tok::plusplus:      // unary-expression: '++' unary-expression [C99]
1315   case tok::minusminus: {  // unary-expression: '--' unary-expression [C99]
1316     if (NotPrimaryExpression)
1317       *NotPrimaryExpression = true;
1318     // C++ [expr.unary] has:
1319     //   unary-expression:
1320     //     ++ cast-expression
1321     //     -- cast-expression
1322     Token SavedTok = Tok;
1323     ConsumeToken();
1324 
1325     PreferredType.enterUnary(Actions, Tok.getLocation(), SavedTok.getKind(),
1326                              SavedTok.getLocation());
1327     // One special case is implicitly handled here: if the preceding tokens are
1328     // an ambiguous cast expression, such as "(T())++", then we recurse to
1329     // determine whether the '++' is prefix or postfix.
1330     Res = ParseCastExpression(getLangOpts().CPlusPlus ?
1331                                   UnaryExprOnly : AnyCastExpr,
1332                               /*isAddressOfOperand*/false, NotCastExpr,
1333                               NotTypeCast);
1334     if (NotCastExpr) {
1335       // If we return with NotCastExpr = true, we must not consume any tokens,
1336       // so put the token back where we found it.
1337       assert(Res.isInvalid());
1338       UnconsumeToken(SavedTok);
1339       return ExprError();
1340     }
1341     if (!Res.isInvalid()) {
1342       Expr *Arg = Res.get();
1343       Res = Actions.ActOnUnaryOp(getCurScope(), SavedTok.getLocation(),
1344                                  SavedKind, Arg);
1345       if (Res.isInvalid())
1346         Res = Actions.CreateRecoveryExpr(SavedTok.getLocation(),
1347                                          Arg->getEndLoc(), Arg);
1348     }
1349     return Res;
1350   }
1351   case tok::amp: {         // unary-expression: '&' cast-expression
1352     if (NotPrimaryExpression)
1353       *NotPrimaryExpression = true;
1354     // Special treatment because of member pointers
1355     SourceLocation SavedLoc = ConsumeToken();
1356     PreferredType.enterUnary(Actions, Tok.getLocation(), tok::amp, SavedLoc);
1357     Res = ParseCastExpression(AnyCastExpr, true);
1358     if (!Res.isInvalid()) {
1359       Expr *Arg = Res.get();
1360       Res = Actions.ActOnUnaryOp(getCurScope(), SavedLoc, SavedKind, Arg);
1361       if (Res.isInvalid())
1362         Res = Actions.CreateRecoveryExpr(Tok.getLocation(), Arg->getEndLoc(),
1363                                          Arg);
1364     }
1365     return Res;
1366   }
1367 
1368   case tok::star:          // unary-expression: '*' cast-expression
1369   case tok::plus:          // unary-expression: '+' cast-expression
1370   case tok::minus:         // unary-expression: '-' cast-expression
1371   case tok::tilde:         // unary-expression: '~' cast-expression
1372   case tok::exclaim:       // unary-expression: '!' cast-expression
1373   case tok::kw___real:     // unary-expression: '__real' cast-expression [GNU]
1374   case tok::kw___imag: {   // unary-expression: '__imag' cast-expression [GNU]
1375     if (NotPrimaryExpression)
1376       *NotPrimaryExpression = true;
1377     SourceLocation SavedLoc = ConsumeToken();
1378     PreferredType.enterUnary(Actions, Tok.getLocation(), SavedKind, SavedLoc);
1379     Res = ParseCastExpression(AnyCastExpr);
1380     if (!Res.isInvalid()) {
1381       Expr *Arg = Res.get();
1382       Res = Actions.ActOnUnaryOp(getCurScope(), SavedLoc, SavedKind, Arg);
1383       if (Res.isInvalid())
1384         Res = Actions.CreateRecoveryExpr(SavedLoc, Arg->getEndLoc(), Arg);
1385     }
1386     return Res;
1387   }
1388 
1389   case tok::kw_co_await: {  // unary-expression: 'co_await' cast-expression
1390     if (NotPrimaryExpression)
1391       *NotPrimaryExpression = true;
1392     SourceLocation CoawaitLoc = ConsumeToken();
1393     Res = ParseCastExpression(AnyCastExpr);
1394     if (!Res.isInvalid())
1395       Res = Actions.ActOnCoawaitExpr(getCurScope(), CoawaitLoc, Res.get());
1396     return Res;
1397   }
1398 
1399   case tok::kw___extension__:{//unary-expression:'__extension__' cast-expr [GNU]
1400     // __extension__ silences extension warnings in the subexpression.
1401     if (NotPrimaryExpression)
1402       *NotPrimaryExpression = true;
1403     ExtensionRAIIObject O(Diags);  // Use RAII to do this.
1404     SourceLocation SavedLoc = ConsumeToken();
1405     Res = ParseCastExpression(AnyCastExpr);
1406     if (!Res.isInvalid())
1407       Res = Actions.ActOnUnaryOp(getCurScope(), SavedLoc, SavedKind, Res.get());
1408     return Res;
1409   }
1410   case tok::kw__Alignof:   // unary-expression: '_Alignof' '(' type-name ')'
1411     if (!getLangOpts().C11)
1412       Diag(Tok, diag::ext_c11_feature) << Tok.getName();
1413     LLVM_FALLTHROUGH;
1414   case tok::kw_alignof:    // unary-expression: 'alignof' '(' type-id ')'
1415   case tok::kw___alignof:  // unary-expression: '__alignof' unary-expression
1416                            // unary-expression: '__alignof' '(' type-name ')'
1417   case tok::kw_sizeof:     // unary-expression: 'sizeof' unary-expression
1418                            // unary-expression: 'sizeof' '(' type-name ')'
1419   case tok::kw_vec_step:   // unary-expression: OpenCL 'vec_step' expression
1420   // unary-expression: '__builtin_omp_required_simd_align' '(' type-name ')'
1421   case tok::kw___builtin_omp_required_simd_align:
1422     if (NotPrimaryExpression)
1423       *NotPrimaryExpression = true;
1424     AllowSuffix = false;
1425     Res = ParseUnaryExprOrTypeTraitExpression();
1426     break;
1427   case tok::ampamp: {      // unary-expression: '&&' identifier
1428     if (NotPrimaryExpression)
1429       *NotPrimaryExpression = true;
1430     SourceLocation AmpAmpLoc = ConsumeToken();
1431     if (Tok.isNot(tok::identifier))
1432       return ExprError(Diag(Tok, diag::err_expected) << tok::identifier);
1433 
1434     if (getCurScope()->getFnParent() == nullptr)
1435       return ExprError(Diag(Tok, diag::err_address_of_label_outside_fn));
1436 
1437     Diag(AmpAmpLoc, diag::ext_gnu_address_of_label);
1438     LabelDecl *LD = Actions.LookupOrCreateLabel(Tok.getIdentifierInfo(),
1439                                                 Tok.getLocation());
1440     Res = Actions.ActOnAddrLabel(AmpAmpLoc, Tok.getLocation(), LD);
1441     ConsumeToken();
1442     AllowSuffix = false;
1443     break;
1444   }
1445   case tok::kw_const_cast:
1446   case tok::kw_dynamic_cast:
1447   case tok::kw_reinterpret_cast:
1448   case tok::kw_static_cast:
1449   case tok::kw_addrspace_cast:
1450     if (NotPrimaryExpression)
1451       *NotPrimaryExpression = true;
1452     Res = ParseCXXCasts();
1453     break;
1454   case tok::kw___builtin_bit_cast:
1455     if (NotPrimaryExpression)
1456       *NotPrimaryExpression = true;
1457     Res = ParseBuiltinBitCast();
1458     break;
1459   case tok::kw_typeid:
1460     if (NotPrimaryExpression)
1461       *NotPrimaryExpression = true;
1462     Res = ParseCXXTypeid();
1463     break;
1464   case tok::kw___uuidof:
1465     if (NotPrimaryExpression)
1466       *NotPrimaryExpression = true;
1467     Res = ParseCXXUuidof();
1468     break;
1469   case tok::kw_this:
1470     Res = ParseCXXThis();
1471     break;
1472 
1473   case tok::annot_typename:
1474     if (isStartOfObjCClassMessageMissingOpenBracket()) {
1475       TypeResult Type = getTypeAnnotation(Tok);
1476 
1477       // Fake up a Declarator to use with ActOnTypeName.
1478       DeclSpec DS(AttrFactory);
1479       DS.SetRangeStart(Tok.getLocation());
1480       DS.SetRangeEnd(Tok.getLastLoc());
1481 
1482       const char *PrevSpec = nullptr;
1483       unsigned DiagID;
1484       DS.SetTypeSpecType(TST_typename, Tok.getAnnotationEndLoc(),
1485                          PrevSpec, DiagID, Type,
1486                          Actions.getASTContext().getPrintingPolicy());
1487 
1488       Declarator DeclaratorInfo(DS, DeclaratorContext::TypeName);
1489       TypeResult Ty = Actions.ActOnTypeName(getCurScope(), DeclaratorInfo);
1490       if (Ty.isInvalid())
1491         break;
1492 
1493       ConsumeAnnotationToken();
1494       Res = ParseObjCMessageExpressionBody(SourceLocation(), SourceLocation(),
1495                                            Ty.get(), nullptr);
1496       break;
1497     }
1498     LLVM_FALLTHROUGH;
1499 
1500   case tok::annot_decltype:
1501   case tok::kw_char:
1502   case tok::kw_wchar_t:
1503   case tok::kw_char8_t:
1504   case tok::kw_char16_t:
1505   case tok::kw_char32_t:
1506   case tok::kw_bool:
1507   case tok::kw_short:
1508   case tok::kw_int:
1509   case tok::kw_long:
1510   case tok::kw___int64:
1511   case tok::kw___int128:
1512   case tok::kw__ExtInt:
1513   case tok::kw_signed:
1514   case tok::kw_unsigned:
1515   case tok::kw_half:
1516   case tok::kw_float:
1517   case tok::kw_double:
1518   case tok::kw___bf16:
1519   case tok::kw__Float16:
1520   case tok::kw___float128:
1521   case tok::kw_void:
1522   case tok::kw_typename:
1523   case tok::kw_typeof:
1524   case tok::kw___vector:
1525 #define GENERIC_IMAGE_TYPE(ImgType, Id) case tok::kw_##ImgType##_t:
1526 #include "clang/Basic/OpenCLImageTypes.def"
1527   {
1528     if (!getLangOpts().CPlusPlus) {
1529       Diag(Tok, diag::err_expected_expression);
1530       return ExprError();
1531     }
1532 
1533     // Everything henceforth is a postfix-expression.
1534     if (NotPrimaryExpression)
1535       *NotPrimaryExpression = true;
1536 
1537     if (SavedKind == tok::kw_typename) {
1538       // postfix-expression: typename-specifier '(' expression-list[opt] ')'
1539       //                     typename-specifier braced-init-list
1540       if (TryAnnotateTypeOrScopeToken())
1541         return ExprError();
1542 
1543       if (!Actions.isSimpleTypeSpecifier(Tok.getKind()))
1544         // We are trying to parse a simple-type-specifier but might not get such
1545         // a token after error recovery.
1546         return ExprError();
1547     }
1548 
1549     // postfix-expression: simple-type-specifier '(' expression-list[opt] ')'
1550     //                     simple-type-specifier braced-init-list
1551     //
1552     DeclSpec DS(AttrFactory);
1553 
1554     ParseCXXSimpleTypeSpecifier(DS);
1555     if (Tok.isNot(tok::l_paren) &&
1556         (!getLangOpts().CPlusPlus11 || Tok.isNot(tok::l_brace)))
1557       return ExprError(Diag(Tok, diag::err_expected_lparen_after_type)
1558                          << DS.getSourceRange());
1559 
1560     if (Tok.is(tok::l_brace))
1561       Diag(Tok, diag::warn_cxx98_compat_generalized_initializer_lists);
1562 
1563     Res = ParseCXXTypeConstructExpression(DS);
1564     break;
1565   }
1566 
1567   case tok::annot_cxxscope: { // [C++] id-expression: qualified-id
1568     // If TryAnnotateTypeOrScopeToken annotates the token, tail recurse.
1569     // (We can end up in this situation after tentative parsing.)
1570     if (TryAnnotateTypeOrScopeToken())
1571       return ExprError();
1572     if (!Tok.is(tok::annot_cxxscope))
1573       return ParseCastExpression(ParseKind, isAddressOfOperand, NotCastExpr,
1574                                  isTypeCast, isVectorLiteral,
1575                                  NotPrimaryExpression);
1576 
1577     Token Next = NextToken();
1578     if (Next.is(tok::annot_template_id)) {
1579       TemplateIdAnnotation *TemplateId = takeTemplateIdAnnotation(Next);
1580       if (TemplateId->Kind == TNK_Type_template) {
1581         // We have a qualified template-id that we know refers to a
1582         // type, translate it into a type and continue parsing as a
1583         // cast expression.
1584         CXXScopeSpec SS;
1585         ParseOptionalCXXScopeSpecifier(SS, /*ObjectType=*/nullptr,
1586                                        /*ObjectHadErrors=*/false,
1587                                        /*EnteringContext=*/false);
1588         AnnotateTemplateIdTokenAsType(SS);
1589         return ParseCastExpression(ParseKind, isAddressOfOperand, NotCastExpr,
1590                                    isTypeCast, isVectorLiteral,
1591                                    NotPrimaryExpression);
1592       }
1593     }
1594 
1595     // Parse as an id-expression.
1596     Res = ParseCXXIdExpression(isAddressOfOperand);
1597     break;
1598   }
1599 
1600   case tok::annot_template_id: { // [C++]          template-id
1601     TemplateIdAnnotation *TemplateId = takeTemplateIdAnnotation(Tok);
1602     if (TemplateId->Kind == TNK_Type_template) {
1603       // We have a template-id that we know refers to a type,
1604       // translate it into a type and continue parsing as a cast
1605       // expression.
1606       CXXScopeSpec SS;
1607       AnnotateTemplateIdTokenAsType(SS);
1608       return ParseCastExpression(ParseKind, isAddressOfOperand,
1609                                  NotCastExpr, isTypeCast, isVectorLiteral,
1610                                  NotPrimaryExpression);
1611     }
1612 
1613     // Fall through to treat the template-id as an id-expression.
1614     LLVM_FALLTHROUGH;
1615   }
1616 
1617   case tok::kw_operator: // [C++] id-expression: operator/conversion-function-id
1618     Res = ParseCXXIdExpression(isAddressOfOperand);
1619     break;
1620 
1621   case tok::coloncolon: {
1622     // ::foo::bar -> global qualified name etc.   If TryAnnotateTypeOrScopeToken
1623     // annotates the token, tail recurse.
1624     if (TryAnnotateTypeOrScopeToken())
1625       return ExprError();
1626     if (!Tok.is(tok::coloncolon))
1627       return ParseCastExpression(ParseKind, isAddressOfOperand, isTypeCast,
1628                                  isVectorLiteral, NotPrimaryExpression);
1629 
1630     // ::new -> [C++] new-expression
1631     // ::delete -> [C++] delete-expression
1632     SourceLocation CCLoc = ConsumeToken();
1633     if (Tok.is(tok::kw_new)) {
1634       if (NotPrimaryExpression)
1635         *NotPrimaryExpression = true;
1636       Res = ParseCXXNewExpression(true, CCLoc);
1637       AllowSuffix = false;
1638       break;
1639     }
1640     if (Tok.is(tok::kw_delete)) {
1641       if (NotPrimaryExpression)
1642         *NotPrimaryExpression = true;
1643       Res = ParseCXXDeleteExpression(true, CCLoc);
1644       AllowSuffix = false;
1645       break;
1646     }
1647 
1648     // This is not a type name or scope specifier, it is an invalid expression.
1649     Diag(CCLoc, diag::err_expected_expression);
1650     return ExprError();
1651   }
1652 
1653   case tok::kw_new: // [C++] new-expression
1654     if (NotPrimaryExpression)
1655       *NotPrimaryExpression = true;
1656     Res = ParseCXXNewExpression(false, Tok.getLocation());
1657     AllowSuffix = false;
1658     break;
1659 
1660   case tok::kw_delete: // [C++] delete-expression
1661     if (NotPrimaryExpression)
1662       *NotPrimaryExpression = true;
1663     Res = ParseCXXDeleteExpression(false, Tok.getLocation());
1664     AllowSuffix = false;
1665     break;
1666 
1667   case tok::kw_requires: // [C++2a] requires-expression
1668     Res = ParseRequiresExpression();
1669     AllowSuffix = false;
1670     break;
1671 
1672   case tok::kw_noexcept: { // [C++0x] 'noexcept' '(' expression ')'
1673     if (NotPrimaryExpression)
1674       *NotPrimaryExpression = true;
1675     Diag(Tok, diag::warn_cxx98_compat_noexcept_expr);
1676     SourceLocation KeyLoc = ConsumeToken();
1677     BalancedDelimiterTracker T(*this, tok::l_paren);
1678 
1679     if (T.expectAndConsume(diag::err_expected_lparen_after, "noexcept"))
1680       return ExprError();
1681     // C++11 [expr.unary.noexcept]p1:
1682     //   The noexcept operator determines whether the evaluation of its operand,
1683     //   which is an unevaluated operand, can throw an exception.
1684     EnterExpressionEvaluationContext Unevaluated(
1685         Actions, Sema::ExpressionEvaluationContext::Unevaluated);
1686     Res = ParseExpression();
1687 
1688     T.consumeClose();
1689 
1690     if (!Res.isInvalid())
1691       Res = Actions.ActOnNoexceptExpr(KeyLoc, T.getOpenLocation(), Res.get(),
1692                                       T.getCloseLocation());
1693     AllowSuffix = false;
1694     break;
1695   }
1696 
1697 #define TYPE_TRAIT(N,Spelling,K) \
1698   case tok::kw_##Spelling:
1699 #include "clang/Basic/TokenKinds.def"
1700     Res = ParseTypeTrait();
1701     break;
1702 
1703   case tok::kw___array_rank:
1704   case tok::kw___array_extent:
1705     if (NotPrimaryExpression)
1706       *NotPrimaryExpression = true;
1707     Res = ParseArrayTypeTrait();
1708     break;
1709 
1710   case tok::kw___is_lvalue_expr:
1711   case tok::kw___is_rvalue_expr:
1712     if (NotPrimaryExpression)
1713       *NotPrimaryExpression = true;
1714     Res = ParseExpressionTrait();
1715     break;
1716 
1717   case tok::at: {
1718     if (NotPrimaryExpression)
1719       *NotPrimaryExpression = true;
1720     SourceLocation AtLoc = ConsumeToken();
1721     return ParseObjCAtExpression(AtLoc);
1722   }
1723   case tok::caret:
1724     Res = ParseBlockLiteralExpression();
1725     break;
1726   case tok::code_completion: {
1727     Actions.CodeCompleteExpression(getCurScope(),
1728                                    PreferredType.get(Tok.getLocation()));
1729     cutOffParsing();
1730     return ExprError();
1731   }
1732   case tok::l_square:
1733     if (getLangOpts().CPlusPlus11) {
1734       if (getLangOpts().ObjC) {
1735         // C++11 lambda expressions and Objective-C message sends both start with a
1736         // square bracket.  There are three possibilities here:
1737         // we have a valid lambda expression, we have an invalid lambda
1738         // expression, or we have something that doesn't appear to be a lambda.
1739         // If we're in the last case, we fall back to ParseObjCMessageExpression.
1740         Res = TryParseLambdaExpression();
1741         if (!Res.isInvalid() && !Res.get()) {
1742           // We assume Objective-C++ message expressions are not
1743           // primary-expressions.
1744           if (NotPrimaryExpression)
1745             *NotPrimaryExpression = true;
1746           Res = ParseObjCMessageExpression();
1747         }
1748         break;
1749       }
1750       Res = ParseLambdaExpression();
1751       break;
1752     }
1753     if (getLangOpts().ObjC) {
1754       Res = ParseObjCMessageExpression();
1755       break;
1756     }
1757     LLVM_FALLTHROUGH;
1758   default:
1759     NotCastExpr = true;
1760     return ExprError();
1761   }
1762 
1763   // Check to see whether Res is a function designator only. If it is and we
1764   // are compiling for OpenCL, we need to return an error as this implies
1765   // that the address of the function is being taken, which is illegal in CL.
1766 
1767   if (ParseKind == PrimaryExprOnly)
1768     // This is strictly a primary-expression - no postfix-expr pieces should be
1769     // parsed.
1770     return Res;
1771 
1772   if (!AllowSuffix) {
1773     // FIXME: Don't parse a primary-expression suffix if we encountered a parse
1774     // error already.
1775     if (Res.isInvalid())
1776       return Res;
1777 
1778     switch (Tok.getKind()) {
1779     case tok::l_square:
1780     case tok::l_paren:
1781     case tok::plusplus:
1782     case tok::minusminus:
1783       // "expected ';'" or similar is probably the right diagnostic here. Let
1784       // the caller decide what to do.
1785       if (Tok.isAtStartOfLine())
1786         return Res;
1787 
1788       LLVM_FALLTHROUGH;
1789     case tok::period:
1790     case tok::arrow:
1791       break;
1792 
1793     default:
1794       return Res;
1795     }
1796 
1797     // This was a unary-expression for which a postfix-expression suffix is
1798     // not permitted by the grammar (eg, a sizeof expression or
1799     // new-expression or similar). Diagnose but parse the suffix anyway.
1800     Diag(Tok.getLocation(), diag::err_postfix_after_unary_requires_parens)
1801         << Tok.getKind() << Res.get()->getSourceRange()
1802         << FixItHint::CreateInsertion(Res.get()->getBeginLoc(), "(")
1803         << FixItHint::CreateInsertion(PP.getLocForEndOfToken(PrevTokLocation),
1804                                       ")");
1805   }
1806 
1807   // These can be followed by postfix-expr pieces.
1808   PreferredType = SavedType;
1809   Res = ParsePostfixExpressionSuffix(Res);
1810   if (getLangOpts().OpenCL)
1811     if (Expr *PostfixExpr = Res.get()) {
1812       QualType Ty = PostfixExpr->getType();
1813       if (!Ty.isNull() && Ty->isFunctionType()) {
1814         Diag(PostfixExpr->getExprLoc(),
1815              diag::err_opencl_taking_function_address_parser);
1816         return ExprError();
1817       }
1818     }
1819 
1820   return Res;
1821 }
1822 
1823 /// Once the leading part of a postfix-expression is parsed, this
1824 /// method parses any suffixes that apply.
1825 ///
1826 /// \verbatim
1827 ///       postfix-expression: [C99 6.5.2]
1828 ///         primary-expression
1829 ///         postfix-expression '[' expression ']'
1830 ///         postfix-expression '[' braced-init-list ']'
1831 ///         postfix-expression '(' argument-expression-list[opt] ')'
1832 ///         postfix-expression '.' identifier
1833 ///         postfix-expression '->' identifier
1834 ///         postfix-expression '++'
1835 ///         postfix-expression '--'
1836 ///         '(' type-name ')' '{' initializer-list '}'
1837 ///         '(' type-name ')' '{' initializer-list ',' '}'
1838 ///
1839 ///       argument-expression-list: [C99 6.5.2]
1840 ///         argument-expression ...[opt]
1841 ///         argument-expression-list ',' assignment-expression ...[opt]
1842 /// \endverbatim
1843 ExprResult
1844 Parser::ParsePostfixExpressionSuffix(ExprResult LHS) {
1845   // Now that the primary-expression piece of the postfix-expression has been
1846   // parsed, see if there are any postfix-expression pieces here.
1847   SourceLocation Loc;
1848   auto SavedType = PreferredType;
1849   while (1) {
1850     // Each iteration relies on preferred type for the whole expression.
1851     PreferredType = SavedType;
1852     switch (Tok.getKind()) {
1853     case tok::code_completion:
1854       if (InMessageExpression)
1855         return LHS;
1856 
1857       Actions.CodeCompletePostfixExpression(
1858           getCurScope(), LHS, PreferredType.get(Tok.getLocation()));
1859       cutOffParsing();
1860       return ExprError();
1861 
1862     case tok::identifier:
1863       // If we see identifier: after an expression, and we're not already in a
1864       // message send, then this is probably a message send with a missing
1865       // opening bracket '['.
1866       if (getLangOpts().ObjC && !InMessageExpression &&
1867           (NextToken().is(tok::colon) || NextToken().is(tok::r_square))) {
1868         LHS = ParseObjCMessageExpressionBody(SourceLocation(), SourceLocation(),
1869                                              nullptr, LHS.get());
1870         break;
1871       }
1872       // Fall through; this isn't a message send.
1873       LLVM_FALLTHROUGH;
1874 
1875     default:  // Not a postfix-expression suffix.
1876       return LHS;
1877     case tok::l_square: {  // postfix-expression: p-e '[' expression ']'
1878       // If we have a array postfix expression that starts on a new line and
1879       // Objective-C is enabled, it is highly likely that the user forgot a
1880       // semicolon after the base expression and that the array postfix-expr is
1881       // actually another message send.  In this case, do some look-ahead to see
1882       // if the contents of the square brackets are obviously not a valid
1883       // expression and recover by pretending there is no suffix.
1884       if (getLangOpts().ObjC && Tok.isAtStartOfLine() &&
1885           isSimpleObjCMessageExpression())
1886         return LHS;
1887 
1888       // Reject array indices starting with a lambda-expression. '[[' is
1889       // reserved for attributes.
1890       if (CheckProhibitedCXX11Attribute()) {
1891         (void)Actions.CorrectDelayedTyposInExpr(LHS);
1892         return ExprError();
1893       }
1894 
1895       BalancedDelimiterTracker T(*this, tok::l_square);
1896       T.consumeOpen();
1897       Loc = T.getOpenLocation();
1898       ExprResult Idx, Length, Stride;
1899       SourceLocation ColonLocFirst, ColonLocSecond;
1900       PreferredType.enterSubscript(Actions, Tok.getLocation(), LHS.get());
1901       if (getLangOpts().CPlusPlus11 && Tok.is(tok::l_brace)) {
1902         Diag(Tok, diag::warn_cxx98_compat_generalized_initializer_lists);
1903         Idx = ParseBraceInitializer();
1904       } else if (getLangOpts().OpenMP) {
1905         ColonProtectionRAIIObject RAII(*this);
1906         // Parse [: or [ expr or [ expr :
1907         if (!Tok.is(tok::colon)) {
1908           // [ expr
1909           Idx = ParseExpression();
1910         }
1911         if (Tok.is(tok::colon)) {
1912           // Consume ':'
1913           ColonLocFirst = ConsumeToken();
1914           if (Tok.isNot(tok::r_square) &&
1915               (getLangOpts().OpenMP < 50 ||
1916                ((Tok.isNot(tok::colon) && getLangOpts().OpenMP >= 50))))
1917             Length = ParseExpression();
1918         }
1919         if (getLangOpts().OpenMP >= 50 &&
1920             (OMPClauseKind == llvm::omp::Clause::OMPC_to ||
1921              OMPClauseKind == llvm::omp::Clause::OMPC_from) &&
1922             Tok.is(tok::colon)) {
1923           // Consume ':'
1924           ColonLocSecond = ConsumeToken();
1925           if (Tok.isNot(tok::r_square)) {
1926             Stride = ParseExpression();
1927           }
1928         }
1929       } else
1930         Idx = ParseExpression();
1931 
1932       SourceLocation RLoc = Tok.getLocation();
1933 
1934       LHS = Actions.CorrectDelayedTyposInExpr(LHS);
1935       Idx = Actions.CorrectDelayedTyposInExpr(Idx);
1936       Length = Actions.CorrectDelayedTyposInExpr(Length);
1937       if (!LHS.isInvalid() && !Idx.isInvalid() && !Length.isInvalid() &&
1938           !Stride.isInvalid() && Tok.is(tok::r_square)) {
1939         if (ColonLocFirst.isValid() || ColonLocSecond.isValid()) {
1940           LHS = Actions.ActOnOMPArraySectionExpr(
1941               LHS.get(), Loc, Idx.get(), ColonLocFirst, ColonLocSecond,
1942               Length.get(), Stride.get(), RLoc);
1943         } else {
1944           LHS = Actions.ActOnArraySubscriptExpr(getCurScope(), LHS.get(), Loc,
1945                                                 Idx.get(), RLoc);
1946         }
1947       } else {
1948         LHS = ExprError();
1949         Idx = ExprError();
1950       }
1951 
1952       // Match the ']'.
1953       T.consumeClose();
1954       break;
1955     }
1956 
1957     case tok::l_paren:         // p-e: p-e '(' argument-expression-list[opt] ')'
1958     case tok::lesslessless: {  // p-e: p-e '<<<' argument-expression-list '>>>'
1959                                //   '(' argument-expression-list[opt] ')'
1960       tok::TokenKind OpKind = Tok.getKind();
1961       InMessageExpressionRAIIObject InMessage(*this, false);
1962 
1963       Expr *ExecConfig = nullptr;
1964 
1965       BalancedDelimiterTracker PT(*this, tok::l_paren);
1966 
1967       if (OpKind == tok::lesslessless) {
1968         ExprVector ExecConfigExprs;
1969         CommaLocsTy ExecConfigCommaLocs;
1970         SourceLocation OpenLoc = ConsumeToken();
1971 
1972         if (ParseSimpleExpressionList(ExecConfigExprs, ExecConfigCommaLocs)) {
1973           (void)Actions.CorrectDelayedTyposInExpr(LHS);
1974           LHS = ExprError();
1975         }
1976 
1977         SourceLocation CloseLoc;
1978         if (TryConsumeToken(tok::greatergreatergreater, CloseLoc)) {
1979         } else if (LHS.isInvalid()) {
1980           SkipUntil(tok::greatergreatergreater, StopAtSemi);
1981         } else {
1982           // There was an error closing the brackets
1983           Diag(Tok, diag::err_expected) << tok::greatergreatergreater;
1984           Diag(OpenLoc, diag::note_matching) << tok::lesslessless;
1985           SkipUntil(tok::greatergreatergreater, StopAtSemi);
1986           LHS = ExprError();
1987         }
1988 
1989         if (!LHS.isInvalid()) {
1990           if (ExpectAndConsume(tok::l_paren))
1991             LHS = ExprError();
1992           else
1993             Loc = PrevTokLocation;
1994         }
1995 
1996         if (!LHS.isInvalid()) {
1997           ExprResult ECResult = Actions.ActOnCUDAExecConfigExpr(getCurScope(),
1998                                     OpenLoc,
1999                                     ExecConfigExprs,
2000                                     CloseLoc);
2001           if (ECResult.isInvalid())
2002             LHS = ExprError();
2003           else
2004             ExecConfig = ECResult.get();
2005         }
2006       } else {
2007         PT.consumeOpen();
2008         Loc = PT.getOpenLocation();
2009       }
2010 
2011       ExprVector ArgExprs;
2012       CommaLocsTy CommaLocs;
2013       auto RunSignatureHelp = [&]() -> QualType {
2014         QualType PreferredType = Actions.ProduceCallSignatureHelp(
2015             getCurScope(), LHS.get(), ArgExprs, PT.getOpenLocation());
2016         CalledSignatureHelp = true;
2017         return PreferredType;
2018       };
2019       if (OpKind == tok::l_paren || !LHS.isInvalid()) {
2020         if (Tok.isNot(tok::r_paren)) {
2021           if (ParseExpressionList(ArgExprs, CommaLocs, [&] {
2022                 PreferredType.enterFunctionArgument(Tok.getLocation(),
2023                                                     RunSignatureHelp);
2024               })) {
2025             (void)Actions.CorrectDelayedTyposInExpr(LHS);
2026             // If we got an error when parsing expression list, we don't call
2027             // the CodeCompleteCall handler inside the parser. So call it here
2028             // to make sure we get overload suggestions even when we are in the
2029             // middle of a parameter.
2030             if (PP.isCodeCompletionReached() && !CalledSignatureHelp)
2031               RunSignatureHelp();
2032             LHS = ExprError();
2033           } else if (LHS.isInvalid()) {
2034             for (auto &E : ArgExprs)
2035               Actions.CorrectDelayedTyposInExpr(E);
2036           }
2037         }
2038       }
2039 
2040       // Match the ')'.
2041       if (LHS.isInvalid()) {
2042         SkipUntil(tok::r_paren, StopAtSemi);
2043       } else if (Tok.isNot(tok::r_paren)) {
2044         bool HadDelayedTypo = false;
2045         if (Actions.CorrectDelayedTyposInExpr(LHS).get() != LHS.get())
2046           HadDelayedTypo = true;
2047         for (auto &E : ArgExprs)
2048           if (Actions.CorrectDelayedTyposInExpr(E).get() != E)
2049             HadDelayedTypo = true;
2050         // If there were delayed typos in the LHS or ArgExprs, call SkipUntil
2051         // instead of PT.consumeClose() to avoid emitting extra diagnostics for
2052         // the unmatched l_paren.
2053         if (HadDelayedTypo)
2054           SkipUntil(tok::r_paren, StopAtSemi);
2055         else
2056           PT.consumeClose();
2057         LHS = ExprError();
2058       } else {
2059         assert(
2060             (ArgExprs.size() == 0 || ArgExprs.size() - 1 == CommaLocs.size()) &&
2061             "Unexpected number of commas!");
2062         Expr *Fn = LHS.get();
2063         SourceLocation RParLoc = Tok.getLocation();
2064         LHS = Actions.ActOnCallExpr(getCurScope(), Fn, Loc, ArgExprs, RParLoc,
2065                                     ExecConfig);
2066         if (LHS.isInvalid()) {
2067           ArgExprs.insert(ArgExprs.begin(), Fn);
2068           LHS =
2069               Actions.CreateRecoveryExpr(Fn->getBeginLoc(), RParLoc, ArgExprs);
2070         }
2071         PT.consumeClose();
2072       }
2073 
2074       break;
2075     }
2076     case tok::arrow:
2077     case tok::period: {
2078       // postfix-expression: p-e '->' template[opt] id-expression
2079       // postfix-expression: p-e '.' template[opt] id-expression
2080       tok::TokenKind OpKind = Tok.getKind();
2081       SourceLocation OpLoc = ConsumeToken();  // Eat the "." or "->" token.
2082 
2083       CXXScopeSpec SS;
2084       ParsedType ObjectType;
2085       bool MayBePseudoDestructor = false;
2086       Expr* OrigLHS = !LHS.isInvalid() ? LHS.get() : nullptr;
2087 
2088       PreferredType.enterMemAccess(Actions, Tok.getLocation(), OrigLHS);
2089 
2090       if (getLangOpts().CPlusPlus && !LHS.isInvalid()) {
2091         Expr *Base = OrigLHS;
2092         const Type* BaseType = Base->getType().getTypePtrOrNull();
2093         if (BaseType && Tok.is(tok::l_paren) &&
2094             (BaseType->isFunctionType() ||
2095              BaseType->isSpecificPlaceholderType(BuiltinType::BoundMember))) {
2096           Diag(OpLoc, diag::err_function_is_not_record)
2097               << OpKind << Base->getSourceRange()
2098               << FixItHint::CreateRemoval(OpLoc);
2099           return ParsePostfixExpressionSuffix(Base);
2100         }
2101 
2102         LHS = Actions.ActOnStartCXXMemberReference(getCurScope(), Base, OpLoc,
2103                                                    OpKind, ObjectType,
2104                                                    MayBePseudoDestructor);
2105         if (LHS.isInvalid()) {
2106           // Clang will try to perform expression based completion as a
2107           // fallback, which is confusing in case of member references. So we
2108           // stop here without any completions.
2109           if (Tok.is(tok::code_completion)) {
2110             cutOffParsing();
2111             return ExprError();
2112           }
2113           break;
2114         }
2115         ParseOptionalCXXScopeSpecifier(
2116             SS, ObjectType, LHS.get() && LHS.get()->containsErrors(),
2117             /*EnteringContext=*/false, &MayBePseudoDestructor);
2118         if (SS.isNotEmpty())
2119           ObjectType = nullptr;
2120       }
2121 
2122       if (Tok.is(tok::code_completion)) {
2123         tok::TokenKind CorrectedOpKind =
2124             OpKind == tok::arrow ? tok::period : tok::arrow;
2125         ExprResult CorrectedLHS(/*Invalid=*/true);
2126         if (getLangOpts().CPlusPlus && OrigLHS) {
2127           // FIXME: Creating a TentativeAnalysisScope from outside Sema is a
2128           // hack.
2129           Sema::TentativeAnalysisScope Trap(Actions);
2130           CorrectedLHS = Actions.ActOnStartCXXMemberReference(
2131               getCurScope(), OrigLHS, OpLoc, CorrectedOpKind, ObjectType,
2132               MayBePseudoDestructor);
2133         }
2134 
2135         Expr *Base = LHS.get();
2136         Expr *CorrectedBase = CorrectedLHS.get();
2137         if (!CorrectedBase && !getLangOpts().CPlusPlus)
2138           CorrectedBase = Base;
2139 
2140         // Code completion for a member access expression.
2141         Actions.CodeCompleteMemberReferenceExpr(
2142             getCurScope(), Base, CorrectedBase, OpLoc, OpKind == tok::arrow,
2143             Base && ExprStatementTokLoc == Base->getBeginLoc(),
2144             PreferredType.get(Tok.getLocation()));
2145 
2146         cutOffParsing();
2147         return ExprError();
2148       }
2149 
2150       if (MayBePseudoDestructor && !LHS.isInvalid()) {
2151         LHS = ParseCXXPseudoDestructor(LHS.get(), OpLoc, OpKind, SS,
2152                                        ObjectType);
2153         break;
2154       }
2155 
2156       // Either the action has told us that this cannot be a
2157       // pseudo-destructor expression (based on the type of base
2158       // expression), or we didn't see a '~' in the right place. We
2159       // can still parse a destructor name here, but in that case it
2160       // names a real destructor.
2161       // Allow explicit constructor calls in Microsoft mode.
2162       // FIXME: Add support for explicit call of template constructor.
2163       SourceLocation TemplateKWLoc;
2164       UnqualifiedId Name;
2165       if (getLangOpts().ObjC && OpKind == tok::period &&
2166           Tok.is(tok::kw_class)) {
2167         // Objective-C++:
2168         //   After a '.' in a member access expression, treat the keyword
2169         //   'class' as if it were an identifier.
2170         //
2171         // This hack allows property access to the 'class' method because it is
2172         // such a common method name. For other C++ keywords that are
2173         // Objective-C method names, one must use the message send syntax.
2174         IdentifierInfo *Id = Tok.getIdentifierInfo();
2175         SourceLocation Loc = ConsumeToken();
2176         Name.setIdentifier(Id, Loc);
2177       } else if (ParseUnqualifiedId(
2178                      SS, ObjectType, LHS.get() && LHS.get()->containsErrors(),
2179                      /*EnteringContext=*/false,
2180                      /*AllowDestructorName=*/true,
2181                      /*AllowConstructorName=*/
2182                      getLangOpts().MicrosoftExt && SS.isNotEmpty(),
2183                      /*AllowDeductionGuide=*/false, &TemplateKWLoc, Name)) {
2184         (void)Actions.CorrectDelayedTyposInExpr(LHS);
2185         LHS = ExprError();
2186       }
2187 
2188       if (!LHS.isInvalid())
2189         LHS = Actions.ActOnMemberAccessExpr(getCurScope(), LHS.get(), OpLoc,
2190                                             OpKind, SS, TemplateKWLoc, Name,
2191                                  CurParsedObjCImpl ? CurParsedObjCImpl->Dcl
2192                                                    : nullptr);
2193       if (!LHS.isInvalid()) {
2194         if (Tok.is(tok::less))
2195           checkPotentialAngleBracket(LHS);
2196       } else if (OrigLHS && Name.isValid()) {
2197         // Preserve the LHS if the RHS is an invalid member.
2198         LHS = Actions.CreateRecoveryExpr(OrigLHS->getBeginLoc(),
2199                                          Name.getEndLoc(), {OrigLHS});
2200       }
2201       break;
2202     }
2203     case tok::plusplus:    // postfix-expression: postfix-expression '++'
2204     case tok::minusminus:  // postfix-expression: postfix-expression '--'
2205       if (!LHS.isInvalid()) {
2206         Expr *Arg = LHS.get();
2207         LHS = Actions.ActOnPostfixUnaryOp(getCurScope(), Tok.getLocation(),
2208                                           Tok.getKind(), Arg);
2209         if (LHS.isInvalid())
2210           LHS = Actions.CreateRecoveryExpr(Arg->getBeginLoc(),
2211                                            Tok.getLocation(), Arg);
2212       }
2213       ConsumeToken();
2214       break;
2215     }
2216   }
2217 }
2218 
2219 /// ParseExprAfterUnaryExprOrTypeTrait - We parsed a typeof/sizeof/alignof/
2220 /// vec_step and we are at the start of an expression or a parenthesized
2221 /// type-id. OpTok is the operand token (typeof/sizeof/alignof). Returns the
2222 /// expression (isCastExpr == false) or the type (isCastExpr == true).
2223 ///
2224 /// \verbatim
2225 ///       unary-expression:  [C99 6.5.3]
2226 ///         'sizeof' unary-expression
2227 ///         'sizeof' '(' type-name ')'
2228 /// [GNU]   '__alignof' unary-expression
2229 /// [GNU]   '__alignof' '(' type-name ')'
2230 /// [C11]   '_Alignof' '(' type-name ')'
2231 /// [C++0x] 'alignof' '(' type-id ')'
2232 ///
2233 /// [GNU]   typeof-specifier:
2234 ///           typeof ( expressions )
2235 ///           typeof ( type-name )
2236 /// [GNU/C++] typeof unary-expression
2237 ///
2238 /// [OpenCL 1.1 6.11.12] vec_step built-in function:
2239 ///           vec_step ( expressions )
2240 ///           vec_step ( type-name )
2241 /// \endverbatim
2242 ExprResult
2243 Parser::ParseExprAfterUnaryExprOrTypeTrait(const Token &OpTok,
2244                                            bool &isCastExpr,
2245                                            ParsedType &CastTy,
2246                                            SourceRange &CastRange) {
2247 
2248   assert(OpTok.isOneOf(tok::kw_typeof, tok::kw_sizeof, tok::kw___alignof,
2249                        tok::kw_alignof, tok::kw__Alignof, tok::kw_vec_step,
2250                        tok::kw___builtin_omp_required_simd_align) &&
2251          "Not a typeof/sizeof/alignof/vec_step expression!");
2252 
2253   ExprResult Operand;
2254 
2255   // If the operand doesn't start with an '(', it must be an expression.
2256   if (Tok.isNot(tok::l_paren)) {
2257     // If construct allows a form without parenthesis, user may forget to put
2258     // pathenthesis around type name.
2259     if (OpTok.isOneOf(tok::kw_sizeof, tok::kw___alignof, tok::kw_alignof,
2260                       tok::kw__Alignof)) {
2261       if (isTypeIdUnambiguously()) {
2262         DeclSpec DS(AttrFactory);
2263         ParseSpecifierQualifierList(DS);
2264         Declarator DeclaratorInfo(DS, DeclaratorContext::TypeName);
2265         ParseDeclarator(DeclaratorInfo);
2266 
2267         SourceLocation LParenLoc = PP.getLocForEndOfToken(OpTok.getLocation());
2268         SourceLocation RParenLoc = PP.getLocForEndOfToken(PrevTokLocation);
2269         if (LParenLoc.isInvalid() || RParenLoc.isInvalid()) {
2270           Diag(OpTok.getLocation(),
2271                diag::err_expected_parentheses_around_typename)
2272               << OpTok.getName();
2273         } else {
2274           Diag(LParenLoc, diag::err_expected_parentheses_around_typename)
2275               << OpTok.getName() << FixItHint::CreateInsertion(LParenLoc, "(")
2276               << FixItHint::CreateInsertion(RParenLoc, ")");
2277         }
2278         isCastExpr = true;
2279         return ExprEmpty();
2280       }
2281     }
2282 
2283     isCastExpr = false;
2284     if (OpTok.is(tok::kw_typeof) && !getLangOpts().CPlusPlus) {
2285       Diag(Tok, diag::err_expected_after) << OpTok.getIdentifierInfo()
2286                                           << tok::l_paren;
2287       return ExprError();
2288     }
2289 
2290     Operand = ParseCastExpression(UnaryExprOnly);
2291   } else {
2292     // If it starts with a '(', we know that it is either a parenthesized
2293     // type-name, or it is a unary-expression that starts with a compound
2294     // literal, or starts with a primary-expression that is a parenthesized
2295     // expression.
2296     ParenParseOption ExprType = CastExpr;
2297     SourceLocation LParenLoc = Tok.getLocation(), RParenLoc;
2298 
2299     Operand = ParseParenExpression(ExprType, true/*stopIfCastExpr*/,
2300                                    false, CastTy, RParenLoc);
2301     CastRange = SourceRange(LParenLoc, RParenLoc);
2302 
2303     // If ParseParenExpression parsed a '(typename)' sequence only, then this is
2304     // a type.
2305     if (ExprType == CastExpr) {
2306       isCastExpr = true;
2307       return ExprEmpty();
2308     }
2309 
2310     if (getLangOpts().CPlusPlus || OpTok.isNot(tok::kw_typeof)) {
2311       // GNU typeof in C requires the expression to be parenthesized. Not so for
2312       // sizeof/alignof or in C++. Therefore, the parenthesized expression is
2313       // the start of a unary-expression, but doesn't include any postfix
2314       // pieces. Parse these now if present.
2315       if (!Operand.isInvalid())
2316         Operand = ParsePostfixExpressionSuffix(Operand.get());
2317     }
2318   }
2319 
2320   // If we get here, the operand to the typeof/sizeof/alignof was an expression.
2321   isCastExpr = false;
2322   return Operand;
2323 }
2324 
2325 
2326 /// Parse a sizeof or alignof expression.
2327 ///
2328 /// \verbatim
2329 ///       unary-expression:  [C99 6.5.3]
2330 ///         'sizeof' unary-expression
2331 ///         'sizeof' '(' type-name ')'
2332 /// [C++11] 'sizeof' '...' '(' identifier ')'
2333 /// [GNU]   '__alignof' unary-expression
2334 /// [GNU]   '__alignof' '(' type-name ')'
2335 /// [C11]   '_Alignof' '(' type-name ')'
2336 /// [C++11] 'alignof' '(' type-id ')'
2337 /// \endverbatim
2338 ExprResult Parser::ParseUnaryExprOrTypeTraitExpression() {
2339   assert(Tok.isOneOf(tok::kw_sizeof, tok::kw___alignof, tok::kw_alignof,
2340                      tok::kw__Alignof, tok::kw_vec_step,
2341                      tok::kw___builtin_omp_required_simd_align) &&
2342          "Not a sizeof/alignof/vec_step expression!");
2343   Token OpTok = Tok;
2344   ConsumeToken();
2345 
2346   // [C++11] 'sizeof' '...' '(' identifier ')'
2347   if (Tok.is(tok::ellipsis) && OpTok.is(tok::kw_sizeof)) {
2348     SourceLocation EllipsisLoc = ConsumeToken();
2349     SourceLocation LParenLoc, RParenLoc;
2350     IdentifierInfo *Name = nullptr;
2351     SourceLocation NameLoc;
2352     if (Tok.is(tok::l_paren)) {
2353       BalancedDelimiterTracker T(*this, tok::l_paren);
2354       T.consumeOpen();
2355       LParenLoc = T.getOpenLocation();
2356       if (Tok.is(tok::identifier)) {
2357         Name = Tok.getIdentifierInfo();
2358         NameLoc = ConsumeToken();
2359         T.consumeClose();
2360         RParenLoc = T.getCloseLocation();
2361         if (RParenLoc.isInvalid())
2362           RParenLoc = PP.getLocForEndOfToken(NameLoc);
2363       } else {
2364         Diag(Tok, diag::err_expected_parameter_pack);
2365         SkipUntil(tok::r_paren, StopAtSemi);
2366       }
2367     } else if (Tok.is(tok::identifier)) {
2368       Name = Tok.getIdentifierInfo();
2369       NameLoc = ConsumeToken();
2370       LParenLoc = PP.getLocForEndOfToken(EllipsisLoc);
2371       RParenLoc = PP.getLocForEndOfToken(NameLoc);
2372       Diag(LParenLoc, diag::err_paren_sizeof_parameter_pack)
2373         << Name
2374         << FixItHint::CreateInsertion(LParenLoc, "(")
2375         << FixItHint::CreateInsertion(RParenLoc, ")");
2376     } else {
2377       Diag(Tok, diag::err_sizeof_parameter_pack);
2378     }
2379 
2380     if (!Name)
2381       return ExprError();
2382 
2383     EnterExpressionEvaluationContext Unevaluated(
2384         Actions, Sema::ExpressionEvaluationContext::Unevaluated,
2385         Sema::ReuseLambdaContextDecl);
2386 
2387     return Actions.ActOnSizeofParameterPackExpr(getCurScope(),
2388                                                 OpTok.getLocation(),
2389                                                 *Name, NameLoc,
2390                                                 RParenLoc);
2391   }
2392 
2393   if (OpTok.isOneOf(tok::kw_alignof, tok::kw__Alignof))
2394     Diag(OpTok, diag::warn_cxx98_compat_alignof);
2395 
2396   EnterExpressionEvaluationContext Unevaluated(
2397       Actions, Sema::ExpressionEvaluationContext::Unevaluated,
2398       Sema::ReuseLambdaContextDecl);
2399 
2400   bool isCastExpr;
2401   ParsedType CastTy;
2402   SourceRange CastRange;
2403   ExprResult Operand = ParseExprAfterUnaryExprOrTypeTrait(OpTok,
2404                                                           isCastExpr,
2405                                                           CastTy,
2406                                                           CastRange);
2407 
2408   UnaryExprOrTypeTrait ExprKind = UETT_SizeOf;
2409   if (OpTok.isOneOf(tok::kw_alignof, tok::kw__Alignof))
2410     ExprKind = UETT_AlignOf;
2411   else if (OpTok.is(tok::kw___alignof))
2412     ExprKind = UETT_PreferredAlignOf;
2413   else if (OpTok.is(tok::kw_vec_step))
2414     ExprKind = UETT_VecStep;
2415   else if (OpTok.is(tok::kw___builtin_omp_required_simd_align))
2416     ExprKind = UETT_OpenMPRequiredSimdAlign;
2417 
2418   if (isCastExpr)
2419     return Actions.ActOnUnaryExprOrTypeTraitExpr(OpTok.getLocation(),
2420                                                  ExprKind,
2421                                                  /*IsType=*/true,
2422                                                  CastTy.getAsOpaquePtr(),
2423                                                  CastRange);
2424 
2425   if (OpTok.isOneOf(tok::kw_alignof, tok::kw__Alignof))
2426     Diag(OpTok, diag::ext_alignof_expr) << OpTok.getIdentifierInfo();
2427 
2428   // If we get here, the operand to the sizeof/alignof was an expression.
2429   if (!Operand.isInvalid())
2430     Operand = Actions.ActOnUnaryExprOrTypeTraitExpr(OpTok.getLocation(),
2431                                                     ExprKind,
2432                                                     /*IsType=*/false,
2433                                                     Operand.get(),
2434                                                     CastRange);
2435   return Operand;
2436 }
2437 
2438 /// ParseBuiltinPrimaryExpression
2439 ///
2440 /// \verbatim
2441 ///       primary-expression: [C99 6.5.1]
2442 /// [GNU]   '__builtin_va_arg' '(' assignment-expression ',' type-name ')'
2443 /// [GNU]   '__builtin_offsetof' '(' type-name ',' offsetof-member-designator')'
2444 /// [GNU]   '__builtin_choose_expr' '(' assign-expr ',' assign-expr ','
2445 ///                                     assign-expr ')'
2446 /// [GNU]   '__builtin_types_compatible_p' '(' type-name ',' type-name ')'
2447 /// [GNU]   '__builtin_FILE' '(' ')'
2448 /// [GNU]   '__builtin_FUNCTION' '(' ')'
2449 /// [GNU]   '__builtin_LINE' '(' ')'
2450 /// [CLANG] '__builtin_COLUMN' '(' ')'
2451 /// [OCL]   '__builtin_astype' '(' assignment-expression ',' type-name ')'
2452 ///
2453 /// [GNU] offsetof-member-designator:
2454 /// [GNU]   identifier
2455 /// [GNU]   offsetof-member-designator '.' identifier
2456 /// [GNU]   offsetof-member-designator '[' expression ']'
2457 /// \endverbatim
2458 ExprResult Parser::ParseBuiltinPrimaryExpression() {
2459   ExprResult Res;
2460   const IdentifierInfo *BuiltinII = Tok.getIdentifierInfo();
2461 
2462   tok::TokenKind T = Tok.getKind();
2463   SourceLocation StartLoc = ConsumeToken();   // Eat the builtin identifier.
2464 
2465   // All of these start with an open paren.
2466   if (Tok.isNot(tok::l_paren))
2467     return ExprError(Diag(Tok, diag::err_expected_after) << BuiltinII
2468                                                          << tok::l_paren);
2469 
2470   BalancedDelimiterTracker PT(*this, tok::l_paren);
2471   PT.consumeOpen();
2472 
2473   // TODO: Build AST.
2474 
2475   switch (T) {
2476   default: llvm_unreachable("Not a builtin primary expression!");
2477   case tok::kw___builtin_va_arg: {
2478     ExprResult Expr(ParseAssignmentExpression());
2479 
2480     if (ExpectAndConsume(tok::comma)) {
2481       SkipUntil(tok::r_paren, StopAtSemi);
2482       Expr = ExprError();
2483     }
2484 
2485     TypeResult Ty = ParseTypeName();
2486 
2487     if (Tok.isNot(tok::r_paren)) {
2488       Diag(Tok, diag::err_expected) << tok::r_paren;
2489       Expr = ExprError();
2490     }
2491 
2492     if (Expr.isInvalid() || Ty.isInvalid())
2493       Res = ExprError();
2494     else
2495       Res = Actions.ActOnVAArg(StartLoc, Expr.get(), Ty.get(), ConsumeParen());
2496     break;
2497   }
2498   case tok::kw___builtin_offsetof: {
2499     SourceLocation TypeLoc = Tok.getLocation();
2500     TypeResult Ty = ParseTypeName();
2501     if (Ty.isInvalid()) {
2502       SkipUntil(tok::r_paren, StopAtSemi);
2503       return ExprError();
2504     }
2505 
2506     if (ExpectAndConsume(tok::comma)) {
2507       SkipUntil(tok::r_paren, StopAtSemi);
2508       return ExprError();
2509     }
2510 
2511     // We must have at least one identifier here.
2512     if (Tok.isNot(tok::identifier)) {
2513       Diag(Tok, diag::err_expected) << tok::identifier;
2514       SkipUntil(tok::r_paren, StopAtSemi);
2515       return ExprError();
2516     }
2517 
2518     // Keep track of the various subcomponents we see.
2519     SmallVector<Sema::OffsetOfComponent, 4> Comps;
2520 
2521     Comps.push_back(Sema::OffsetOfComponent());
2522     Comps.back().isBrackets = false;
2523     Comps.back().U.IdentInfo = Tok.getIdentifierInfo();
2524     Comps.back().LocStart = Comps.back().LocEnd = ConsumeToken();
2525 
2526     // FIXME: This loop leaks the index expressions on error.
2527     while (1) {
2528       if (Tok.is(tok::period)) {
2529         // offsetof-member-designator: offsetof-member-designator '.' identifier
2530         Comps.push_back(Sema::OffsetOfComponent());
2531         Comps.back().isBrackets = false;
2532         Comps.back().LocStart = ConsumeToken();
2533 
2534         if (Tok.isNot(tok::identifier)) {
2535           Diag(Tok, diag::err_expected) << tok::identifier;
2536           SkipUntil(tok::r_paren, StopAtSemi);
2537           return ExprError();
2538         }
2539         Comps.back().U.IdentInfo = Tok.getIdentifierInfo();
2540         Comps.back().LocEnd = ConsumeToken();
2541 
2542       } else if (Tok.is(tok::l_square)) {
2543         if (CheckProhibitedCXX11Attribute())
2544           return ExprError();
2545 
2546         // offsetof-member-designator: offsetof-member-design '[' expression ']'
2547         Comps.push_back(Sema::OffsetOfComponent());
2548         Comps.back().isBrackets = true;
2549         BalancedDelimiterTracker ST(*this, tok::l_square);
2550         ST.consumeOpen();
2551         Comps.back().LocStart = ST.getOpenLocation();
2552         Res = ParseExpression();
2553         if (Res.isInvalid()) {
2554           SkipUntil(tok::r_paren, StopAtSemi);
2555           return Res;
2556         }
2557         Comps.back().U.E = Res.get();
2558 
2559         ST.consumeClose();
2560         Comps.back().LocEnd = ST.getCloseLocation();
2561       } else {
2562         if (Tok.isNot(tok::r_paren)) {
2563           PT.consumeClose();
2564           Res = ExprError();
2565         } else if (Ty.isInvalid()) {
2566           Res = ExprError();
2567         } else {
2568           PT.consumeClose();
2569           Res = Actions.ActOnBuiltinOffsetOf(getCurScope(), StartLoc, TypeLoc,
2570                                              Ty.get(), Comps,
2571                                              PT.getCloseLocation());
2572         }
2573         break;
2574       }
2575     }
2576     break;
2577   }
2578   case tok::kw___builtin_choose_expr: {
2579     ExprResult Cond(ParseAssignmentExpression());
2580     if (Cond.isInvalid()) {
2581       SkipUntil(tok::r_paren, StopAtSemi);
2582       return Cond;
2583     }
2584     if (ExpectAndConsume(tok::comma)) {
2585       SkipUntil(tok::r_paren, StopAtSemi);
2586       return ExprError();
2587     }
2588 
2589     ExprResult Expr1(ParseAssignmentExpression());
2590     if (Expr1.isInvalid()) {
2591       SkipUntil(tok::r_paren, StopAtSemi);
2592       return Expr1;
2593     }
2594     if (ExpectAndConsume(tok::comma)) {
2595       SkipUntil(tok::r_paren, StopAtSemi);
2596       return ExprError();
2597     }
2598 
2599     ExprResult Expr2(ParseAssignmentExpression());
2600     if (Expr2.isInvalid()) {
2601       SkipUntil(tok::r_paren, StopAtSemi);
2602       return Expr2;
2603     }
2604     if (Tok.isNot(tok::r_paren)) {
2605       Diag(Tok, diag::err_expected) << tok::r_paren;
2606       return ExprError();
2607     }
2608     Res = Actions.ActOnChooseExpr(StartLoc, Cond.get(), Expr1.get(),
2609                                   Expr2.get(), ConsumeParen());
2610     break;
2611   }
2612   case tok::kw___builtin_astype: {
2613     // The first argument is an expression to be converted, followed by a comma.
2614     ExprResult Expr(ParseAssignmentExpression());
2615     if (Expr.isInvalid()) {
2616       SkipUntil(tok::r_paren, StopAtSemi);
2617       return ExprError();
2618     }
2619 
2620     if (ExpectAndConsume(tok::comma)) {
2621       SkipUntil(tok::r_paren, StopAtSemi);
2622       return ExprError();
2623     }
2624 
2625     // Second argument is the type to bitcast to.
2626     TypeResult DestTy = ParseTypeName();
2627     if (DestTy.isInvalid())
2628       return ExprError();
2629 
2630     // Attempt to consume the r-paren.
2631     if (Tok.isNot(tok::r_paren)) {
2632       Diag(Tok, diag::err_expected) << tok::r_paren;
2633       SkipUntil(tok::r_paren, StopAtSemi);
2634       return ExprError();
2635     }
2636 
2637     Res = Actions.ActOnAsTypeExpr(Expr.get(), DestTy.get(), StartLoc,
2638                                   ConsumeParen());
2639     break;
2640   }
2641   case tok::kw___builtin_convertvector: {
2642     // The first argument is an expression to be converted, followed by a comma.
2643     ExprResult Expr(ParseAssignmentExpression());
2644     if (Expr.isInvalid()) {
2645       SkipUntil(tok::r_paren, StopAtSemi);
2646       return ExprError();
2647     }
2648 
2649     if (ExpectAndConsume(tok::comma)) {
2650       SkipUntil(tok::r_paren, StopAtSemi);
2651       return ExprError();
2652     }
2653 
2654     // Second argument is the type to bitcast to.
2655     TypeResult DestTy = ParseTypeName();
2656     if (DestTy.isInvalid())
2657       return ExprError();
2658 
2659     // Attempt to consume the r-paren.
2660     if (Tok.isNot(tok::r_paren)) {
2661       Diag(Tok, diag::err_expected) << tok::r_paren;
2662       SkipUntil(tok::r_paren, StopAtSemi);
2663       return ExprError();
2664     }
2665 
2666     Res = Actions.ActOnConvertVectorExpr(Expr.get(), DestTy.get(), StartLoc,
2667                                          ConsumeParen());
2668     break;
2669   }
2670   case tok::kw___builtin_COLUMN:
2671   case tok::kw___builtin_FILE:
2672   case tok::kw___builtin_FUNCTION:
2673   case tok::kw___builtin_LINE: {
2674     // Attempt to consume the r-paren.
2675     if (Tok.isNot(tok::r_paren)) {
2676       Diag(Tok, diag::err_expected) << tok::r_paren;
2677       SkipUntil(tok::r_paren, StopAtSemi);
2678       return ExprError();
2679     }
2680     SourceLocExpr::IdentKind Kind = [&] {
2681       switch (T) {
2682       case tok::kw___builtin_FILE:
2683         return SourceLocExpr::File;
2684       case tok::kw___builtin_FUNCTION:
2685         return SourceLocExpr::Function;
2686       case tok::kw___builtin_LINE:
2687         return SourceLocExpr::Line;
2688       case tok::kw___builtin_COLUMN:
2689         return SourceLocExpr::Column;
2690       default:
2691         llvm_unreachable("invalid keyword");
2692       }
2693     }();
2694     Res = Actions.ActOnSourceLocExpr(Kind, StartLoc, ConsumeParen());
2695     break;
2696   }
2697   }
2698 
2699   if (Res.isInvalid())
2700     return ExprError();
2701 
2702   // These can be followed by postfix-expr pieces because they are
2703   // primary-expressions.
2704   return ParsePostfixExpressionSuffix(Res.get());
2705 }
2706 
2707 bool Parser::tryParseOpenMPArrayShapingCastPart() {
2708   assert(Tok.is(tok::l_square) && "Expected open bracket");
2709   bool ErrorFound = true;
2710   TentativeParsingAction TPA(*this);
2711   do {
2712     if (Tok.isNot(tok::l_square))
2713       break;
2714     // Consume '['
2715     ConsumeBracket();
2716     // Skip inner expression.
2717     while (!SkipUntil(tok::r_square, tok::annot_pragma_openmp_end,
2718                       StopAtSemi | StopBeforeMatch))
2719       ;
2720     if (Tok.isNot(tok::r_square))
2721       break;
2722     // Consume ']'
2723     ConsumeBracket();
2724     // Found ')' - done.
2725     if (Tok.is(tok::r_paren)) {
2726       ErrorFound = false;
2727       break;
2728     }
2729   } while (Tok.isNot(tok::annot_pragma_openmp_end));
2730   TPA.Revert();
2731   return !ErrorFound;
2732 }
2733 
2734 /// ParseParenExpression - This parses the unit that starts with a '(' token,
2735 /// based on what is allowed by ExprType.  The actual thing parsed is returned
2736 /// in ExprType. If stopIfCastExpr is true, it will only return the parsed type,
2737 /// not the parsed cast-expression.
2738 ///
2739 /// \verbatim
2740 ///       primary-expression: [C99 6.5.1]
2741 ///         '(' expression ')'
2742 /// [GNU]   '(' compound-statement ')'      (if !ParenExprOnly)
2743 ///       postfix-expression: [C99 6.5.2]
2744 ///         '(' type-name ')' '{' initializer-list '}'
2745 ///         '(' type-name ')' '{' initializer-list ',' '}'
2746 ///       cast-expression: [C99 6.5.4]
2747 ///         '(' type-name ')' cast-expression
2748 /// [ARC]   bridged-cast-expression
2749 /// [ARC] bridged-cast-expression:
2750 ///         (__bridge type-name) cast-expression
2751 ///         (__bridge_transfer type-name) cast-expression
2752 ///         (__bridge_retained type-name) cast-expression
2753 ///       fold-expression: [C++1z]
2754 ///         '(' cast-expression fold-operator '...' ')'
2755 ///         '(' '...' fold-operator cast-expression ')'
2756 ///         '(' cast-expression fold-operator '...'
2757 ///                 fold-operator cast-expression ')'
2758 /// [OPENMP] Array shaping operation
2759 ///       '(' '[' expression ']' { '[' expression ']' } cast-expression
2760 /// \endverbatim
2761 ExprResult
2762 Parser::ParseParenExpression(ParenParseOption &ExprType, bool stopIfCastExpr,
2763                              bool isTypeCast, ParsedType &CastTy,
2764                              SourceLocation &RParenLoc) {
2765   assert(Tok.is(tok::l_paren) && "Not a paren expr!");
2766   ColonProtectionRAIIObject ColonProtection(*this, false);
2767   BalancedDelimiterTracker T(*this, tok::l_paren);
2768   if (T.consumeOpen())
2769     return ExprError();
2770   SourceLocation OpenLoc = T.getOpenLocation();
2771 
2772   PreferredType.enterParenExpr(Tok.getLocation(), OpenLoc);
2773 
2774   ExprResult Result(true);
2775   bool isAmbiguousTypeId;
2776   CastTy = nullptr;
2777 
2778   if (Tok.is(tok::code_completion)) {
2779     Actions.CodeCompleteExpression(
2780         getCurScope(), PreferredType.get(Tok.getLocation()),
2781         /*IsParenthesized=*/ExprType >= CompoundLiteral);
2782     cutOffParsing();
2783     return ExprError();
2784   }
2785 
2786   // Diagnose use of bridge casts in non-arc mode.
2787   bool BridgeCast = (getLangOpts().ObjC &&
2788                      Tok.isOneOf(tok::kw___bridge,
2789                                  tok::kw___bridge_transfer,
2790                                  tok::kw___bridge_retained,
2791                                  tok::kw___bridge_retain));
2792   if (BridgeCast && !getLangOpts().ObjCAutoRefCount) {
2793     if (!TryConsumeToken(tok::kw___bridge)) {
2794       StringRef BridgeCastName = Tok.getName();
2795       SourceLocation BridgeKeywordLoc = ConsumeToken();
2796       if (!PP.getSourceManager().isInSystemHeader(BridgeKeywordLoc))
2797         Diag(BridgeKeywordLoc, diag::warn_arc_bridge_cast_nonarc)
2798           << BridgeCastName
2799           << FixItHint::CreateReplacement(BridgeKeywordLoc, "");
2800     }
2801     BridgeCast = false;
2802   }
2803 
2804   // None of these cases should fall through with an invalid Result
2805   // unless they've already reported an error.
2806   if (ExprType >= CompoundStmt && Tok.is(tok::l_brace)) {
2807     Diag(Tok, diag::ext_gnu_statement_expr);
2808 
2809     checkCompoundToken(OpenLoc, tok::l_paren, CompoundToken::StmtExprBegin);
2810 
2811     if (!getCurScope()->getFnParent() && !getCurScope()->getBlockParent()) {
2812       Result = ExprError(Diag(OpenLoc, diag::err_stmtexpr_file_scope));
2813     } else {
2814       // Find the nearest non-record decl context. Variables declared in a
2815       // statement expression behave as if they were declared in the enclosing
2816       // function, block, or other code construct.
2817       DeclContext *CodeDC = Actions.CurContext;
2818       while (CodeDC->isRecord() || isa<EnumDecl>(CodeDC)) {
2819         CodeDC = CodeDC->getParent();
2820         assert(CodeDC && !CodeDC->isFileContext() &&
2821                "statement expr not in code context");
2822       }
2823       Sema::ContextRAII SavedContext(Actions, CodeDC, /*NewThisContext=*/false);
2824 
2825       Actions.ActOnStartStmtExpr();
2826 
2827       StmtResult Stmt(ParseCompoundStatement(true));
2828       ExprType = CompoundStmt;
2829 
2830       // If the substmt parsed correctly, build the AST node.
2831       if (!Stmt.isInvalid()) {
2832         Result = Actions.ActOnStmtExpr(getCurScope(), OpenLoc, Stmt.get(),
2833                                        Tok.getLocation());
2834       } else {
2835         Actions.ActOnStmtExprError();
2836       }
2837     }
2838   } else if (ExprType >= CompoundLiteral && BridgeCast) {
2839     tok::TokenKind tokenKind = Tok.getKind();
2840     SourceLocation BridgeKeywordLoc = ConsumeToken();
2841 
2842     // Parse an Objective-C ARC ownership cast expression.
2843     ObjCBridgeCastKind Kind;
2844     if (tokenKind == tok::kw___bridge)
2845       Kind = OBC_Bridge;
2846     else if (tokenKind == tok::kw___bridge_transfer)
2847       Kind = OBC_BridgeTransfer;
2848     else if (tokenKind == tok::kw___bridge_retained)
2849       Kind = OBC_BridgeRetained;
2850     else {
2851       // As a hopefully temporary workaround, allow __bridge_retain as
2852       // a synonym for __bridge_retained, but only in system headers.
2853       assert(tokenKind == tok::kw___bridge_retain);
2854       Kind = OBC_BridgeRetained;
2855       if (!PP.getSourceManager().isInSystemHeader(BridgeKeywordLoc))
2856         Diag(BridgeKeywordLoc, diag::err_arc_bridge_retain)
2857           << FixItHint::CreateReplacement(BridgeKeywordLoc,
2858                                           "__bridge_retained");
2859     }
2860 
2861     TypeResult Ty = ParseTypeName();
2862     T.consumeClose();
2863     ColonProtection.restore();
2864     RParenLoc = T.getCloseLocation();
2865 
2866     PreferredType.enterTypeCast(Tok.getLocation(), Ty.get().get());
2867     ExprResult SubExpr = ParseCastExpression(AnyCastExpr);
2868 
2869     if (Ty.isInvalid() || SubExpr.isInvalid())
2870       return ExprError();
2871 
2872     return Actions.ActOnObjCBridgedCast(getCurScope(), OpenLoc, Kind,
2873                                         BridgeKeywordLoc, Ty.get(),
2874                                         RParenLoc, SubExpr.get());
2875   } else if (ExprType >= CompoundLiteral &&
2876              isTypeIdInParens(isAmbiguousTypeId)) {
2877 
2878     // Otherwise, this is a compound literal expression or cast expression.
2879 
2880     // In C++, if the type-id is ambiguous we disambiguate based on context.
2881     // If stopIfCastExpr is true the context is a typeof/sizeof/alignof
2882     // in which case we should treat it as type-id.
2883     // if stopIfCastExpr is false, we need to determine the context past the
2884     // parens, so we defer to ParseCXXAmbiguousParenExpression for that.
2885     if (isAmbiguousTypeId && !stopIfCastExpr) {
2886       ExprResult res = ParseCXXAmbiguousParenExpression(ExprType, CastTy, T,
2887                                                         ColonProtection);
2888       RParenLoc = T.getCloseLocation();
2889       return res;
2890     }
2891 
2892     // Parse the type declarator.
2893     DeclSpec DS(AttrFactory);
2894     ParseSpecifierQualifierList(DS);
2895     Declarator DeclaratorInfo(DS, DeclaratorContext::TypeName);
2896     ParseDeclarator(DeclaratorInfo);
2897 
2898     // If our type is followed by an identifier and either ':' or ']', then
2899     // this is probably an Objective-C message send where the leading '[' is
2900     // missing. Recover as if that were the case.
2901     if (!DeclaratorInfo.isInvalidType() && Tok.is(tok::identifier) &&
2902         !InMessageExpression && getLangOpts().ObjC &&
2903         (NextToken().is(tok::colon) || NextToken().is(tok::r_square))) {
2904       TypeResult Ty;
2905       {
2906         InMessageExpressionRAIIObject InMessage(*this, false);
2907         Ty = Actions.ActOnTypeName(getCurScope(), DeclaratorInfo);
2908       }
2909       Result = ParseObjCMessageExpressionBody(SourceLocation(),
2910                                               SourceLocation(),
2911                                               Ty.get(), nullptr);
2912     } else {
2913       // Match the ')'.
2914       T.consumeClose();
2915       ColonProtection.restore();
2916       RParenLoc = T.getCloseLocation();
2917       if (Tok.is(tok::l_brace)) {
2918         ExprType = CompoundLiteral;
2919         TypeResult Ty;
2920         {
2921           InMessageExpressionRAIIObject InMessage(*this, false);
2922           Ty = Actions.ActOnTypeName(getCurScope(), DeclaratorInfo);
2923         }
2924         return ParseCompoundLiteralExpression(Ty.get(), OpenLoc, RParenLoc);
2925       }
2926 
2927       if (Tok.is(tok::l_paren)) {
2928         // This could be OpenCL vector Literals
2929         if (getLangOpts().OpenCL)
2930         {
2931           TypeResult Ty;
2932           {
2933             InMessageExpressionRAIIObject InMessage(*this, false);
2934             Ty = Actions.ActOnTypeName(getCurScope(), DeclaratorInfo);
2935           }
2936           if(Ty.isInvalid())
2937           {
2938              return ExprError();
2939           }
2940           QualType QT = Ty.get().get().getCanonicalType();
2941           if (QT->isVectorType())
2942           {
2943             // We parsed '(' vector-type-name ')' followed by '('
2944 
2945             // Parse the cast-expression that follows it next.
2946             // isVectorLiteral = true will make sure we don't parse any
2947             // Postfix expression yet
2948             Result = ParseCastExpression(/*isUnaryExpression=*/AnyCastExpr,
2949                                          /*isAddressOfOperand=*/false,
2950                                          /*isTypeCast=*/IsTypeCast,
2951                                          /*isVectorLiteral=*/true);
2952 
2953             if (!Result.isInvalid()) {
2954               Result = Actions.ActOnCastExpr(getCurScope(), OpenLoc,
2955                                              DeclaratorInfo, CastTy,
2956                                              RParenLoc, Result.get());
2957             }
2958 
2959             // After we performed the cast we can check for postfix-expr pieces.
2960             if (!Result.isInvalid()) {
2961               Result = ParsePostfixExpressionSuffix(Result);
2962             }
2963 
2964             return Result;
2965           }
2966         }
2967       }
2968 
2969       if (ExprType == CastExpr) {
2970         // We parsed '(' type-name ')' and the thing after it wasn't a '{'.
2971 
2972         if (DeclaratorInfo.isInvalidType())
2973           return ExprError();
2974 
2975         // Note that this doesn't parse the subsequent cast-expression, it just
2976         // returns the parsed type to the callee.
2977         if (stopIfCastExpr) {
2978           TypeResult Ty;
2979           {
2980             InMessageExpressionRAIIObject InMessage(*this, false);
2981             Ty = Actions.ActOnTypeName(getCurScope(), DeclaratorInfo);
2982           }
2983           CastTy = Ty.get();
2984           return ExprResult();
2985         }
2986 
2987         // Reject the cast of super idiom in ObjC.
2988         if (Tok.is(tok::identifier) && getLangOpts().ObjC &&
2989             Tok.getIdentifierInfo() == Ident_super &&
2990             getCurScope()->isInObjcMethodScope() &&
2991             GetLookAheadToken(1).isNot(tok::period)) {
2992           Diag(Tok.getLocation(), diag::err_illegal_super_cast)
2993             << SourceRange(OpenLoc, RParenLoc);
2994           return ExprError();
2995         }
2996 
2997         PreferredType.enterTypeCast(Tok.getLocation(), CastTy.get());
2998         // Parse the cast-expression that follows it next.
2999         // TODO: For cast expression with CastTy.
3000         Result = ParseCastExpression(/*isUnaryExpression=*/AnyCastExpr,
3001                                      /*isAddressOfOperand=*/false,
3002                                      /*isTypeCast=*/IsTypeCast);
3003         if (!Result.isInvalid()) {
3004           Result = Actions.ActOnCastExpr(getCurScope(), OpenLoc,
3005                                          DeclaratorInfo, CastTy,
3006                                          RParenLoc, Result.get());
3007         }
3008         return Result;
3009       }
3010 
3011       Diag(Tok, diag::err_expected_lbrace_in_compound_literal);
3012       return ExprError();
3013     }
3014   } else if (ExprType >= FoldExpr && Tok.is(tok::ellipsis) &&
3015              isFoldOperator(NextToken().getKind())) {
3016     ExprType = FoldExpr;
3017     return ParseFoldExpression(ExprResult(), T);
3018   } else if (isTypeCast) {
3019     // Parse the expression-list.
3020     InMessageExpressionRAIIObject InMessage(*this, false);
3021 
3022     ExprVector ArgExprs;
3023     CommaLocsTy CommaLocs;
3024 
3025     if (!ParseSimpleExpressionList(ArgExprs, CommaLocs)) {
3026       // FIXME: If we ever support comma expressions as operands to
3027       // fold-expressions, we'll need to allow multiple ArgExprs here.
3028       if (ExprType >= FoldExpr && ArgExprs.size() == 1 &&
3029           isFoldOperator(Tok.getKind()) && NextToken().is(tok::ellipsis)) {
3030         ExprType = FoldExpr;
3031         return ParseFoldExpression(ArgExprs[0], T);
3032       }
3033 
3034       ExprType = SimpleExpr;
3035       Result = Actions.ActOnParenListExpr(OpenLoc, Tok.getLocation(),
3036                                           ArgExprs);
3037     }
3038   } else if (getLangOpts().OpenMP >= 50 && OpenMPDirectiveParsing &&
3039              ExprType == CastExpr && Tok.is(tok::l_square) &&
3040              tryParseOpenMPArrayShapingCastPart()) {
3041     bool ErrorFound = false;
3042     SmallVector<Expr *, 4> OMPDimensions;
3043     SmallVector<SourceRange, 4> OMPBracketsRanges;
3044     do {
3045       BalancedDelimiterTracker TS(*this, tok::l_square);
3046       TS.consumeOpen();
3047       ExprResult NumElements =
3048           Actions.CorrectDelayedTyposInExpr(ParseExpression());
3049       if (!NumElements.isUsable()) {
3050         ErrorFound = true;
3051         while (!SkipUntil(tok::r_square, tok::r_paren,
3052                           StopAtSemi | StopBeforeMatch))
3053           ;
3054       }
3055       TS.consumeClose();
3056       OMPDimensions.push_back(NumElements.get());
3057       OMPBracketsRanges.push_back(TS.getRange());
3058     } while (Tok.isNot(tok::r_paren));
3059     // Match the ')'.
3060     T.consumeClose();
3061     RParenLoc = T.getCloseLocation();
3062     Result = Actions.CorrectDelayedTyposInExpr(ParseAssignmentExpression());
3063     if (ErrorFound) {
3064       Result = ExprError();
3065     } else if (!Result.isInvalid()) {
3066       Result = Actions.ActOnOMPArrayShapingExpr(
3067           Result.get(), OpenLoc, RParenLoc, OMPDimensions, OMPBracketsRanges);
3068     }
3069     return Result;
3070   } else {
3071     InMessageExpressionRAIIObject InMessage(*this, false);
3072 
3073     Result = ParseExpression(MaybeTypeCast);
3074     if (!getLangOpts().CPlusPlus && MaybeTypeCast && Result.isUsable()) {
3075       // Correct typos in non-C++ code earlier so that implicit-cast-like
3076       // expressions are parsed correctly.
3077       Result = Actions.CorrectDelayedTyposInExpr(Result);
3078     }
3079 
3080     if (ExprType >= FoldExpr && isFoldOperator(Tok.getKind()) &&
3081         NextToken().is(tok::ellipsis)) {
3082       ExprType = FoldExpr;
3083       return ParseFoldExpression(Result, T);
3084     }
3085     ExprType = SimpleExpr;
3086 
3087     // Don't build a paren expression unless we actually match a ')'.
3088     if (!Result.isInvalid() && Tok.is(tok::r_paren))
3089       Result =
3090           Actions.ActOnParenExpr(OpenLoc, Tok.getLocation(), Result.get());
3091   }
3092 
3093   // Match the ')'.
3094   if (Result.isInvalid()) {
3095     SkipUntil(tok::r_paren, StopAtSemi);
3096     return ExprError();
3097   }
3098 
3099   T.consumeClose();
3100   RParenLoc = T.getCloseLocation();
3101   return Result;
3102 }
3103 
3104 /// ParseCompoundLiteralExpression - We have parsed the parenthesized type-name
3105 /// and we are at the left brace.
3106 ///
3107 /// \verbatim
3108 ///       postfix-expression: [C99 6.5.2]
3109 ///         '(' type-name ')' '{' initializer-list '}'
3110 ///         '(' type-name ')' '{' initializer-list ',' '}'
3111 /// \endverbatim
3112 ExprResult
3113 Parser::ParseCompoundLiteralExpression(ParsedType Ty,
3114                                        SourceLocation LParenLoc,
3115                                        SourceLocation RParenLoc) {
3116   assert(Tok.is(tok::l_brace) && "Not a compound literal!");
3117   if (!getLangOpts().C99)   // Compound literals don't exist in C90.
3118     Diag(LParenLoc, diag::ext_c99_compound_literal);
3119   PreferredType.enterTypeCast(Tok.getLocation(), Ty.get());
3120   ExprResult Result = ParseInitializer();
3121   if (!Result.isInvalid() && Ty)
3122     return Actions.ActOnCompoundLiteral(LParenLoc, Ty, RParenLoc, Result.get());
3123   return Result;
3124 }
3125 
3126 /// ParseStringLiteralExpression - This handles the various token types that
3127 /// form string literals, and also handles string concatenation [C99 5.1.1.2,
3128 /// translation phase #6].
3129 ///
3130 /// \verbatim
3131 ///       primary-expression: [C99 6.5.1]
3132 ///         string-literal
3133 /// \verbatim
3134 ExprResult Parser::ParseStringLiteralExpression(bool AllowUserDefinedLiteral) {
3135   assert(isTokenStringLiteral() && "Not a string literal!");
3136 
3137   // String concat.  Note that keywords like __func__ and __FUNCTION__ are not
3138   // considered to be strings for concatenation purposes.
3139   SmallVector<Token, 4> StringToks;
3140 
3141   do {
3142     StringToks.push_back(Tok);
3143     ConsumeStringToken();
3144   } while (isTokenStringLiteral());
3145 
3146   // Pass the set of string tokens, ready for concatenation, to the actions.
3147   return Actions.ActOnStringLiteral(StringToks,
3148                                     AllowUserDefinedLiteral ? getCurScope()
3149                                                             : nullptr);
3150 }
3151 
3152 /// ParseGenericSelectionExpression - Parse a C11 generic-selection
3153 /// [C11 6.5.1.1].
3154 ///
3155 /// \verbatim
3156 ///    generic-selection:
3157 ///           _Generic ( assignment-expression , generic-assoc-list )
3158 ///    generic-assoc-list:
3159 ///           generic-association
3160 ///           generic-assoc-list , generic-association
3161 ///    generic-association:
3162 ///           type-name : assignment-expression
3163 ///           default : assignment-expression
3164 /// \endverbatim
3165 ExprResult Parser::ParseGenericSelectionExpression() {
3166   assert(Tok.is(tok::kw__Generic) && "_Generic keyword expected");
3167   if (!getLangOpts().C11)
3168     Diag(Tok, diag::ext_c11_feature) << Tok.getName();
3169 
3170   SourceLocation KeyLoc = ConsumeToken();
3171   BalancedDelimiterTracker T(*this, tok::l_paren);
3172   if (T.expectAndConsume())
3173     return ExprError();
3174 
3175   ExprResult ControllingExpr;
3176   {
3177     // C11 6.5.1.1p3 "The controlling expression of a generic selection is
3178     // not evaluated."
3179     EnterExpressionEvaluationContext Unevaluated(
3180         Actions, Sema::ExpressionEvaluationContext::Unevaluated);
3181     ControllingExpr =
3182         Actions.CorrectDelayedTyposInExpr(ParseAssignmentExpression());
3183     if (ControllingExpr.isInvalid()) {
3184       SkipUntil(tok::r_paren, StopAtSemi);
3185       return ExprError();
3186     }
3187   }
3188 
3189   if (ExpectAndConsume(tok::comma)) {
3190     SkipUntil(tok::r_paren, StopAtSemi);
3191     return ExprError();
3192   }
3193 
3194   SourceLocation DefaultLoc;
3195   TypeVector Types;
3196   ExprVector Exprs;
3197   do {
3198     ParsedType Ty;
3199     if (Tok.is(tok::kw_default)) {
3200       // C11 6.5.1.1p2 "A generic selection shall have no more than one default
3201       // generic association."
3202       if (!DefaultLoc.isInvalid()) {
3203         Diag(Tok, diag::err_duplicate_default_assoc);
3204         Diag(DefaultLoc, diag::note_previous_default_assoc);
3205         SkipUntil(tok::r_paren, StopAtSemi);
3206         return ExprError();
3207       }
3208       DefaultLoc = ConsumeToken();
3209       Ty = nullptr;
3210     } else {
3211       ColonProtectionRAIIObject X(*this);
3212       TypeResult TR = ParseTypeName();
3213       if (TR.isInvalid()) {
3214         SkipUntil(tok::r_paren, StopAtSemi);
3215         return ExprError();
3216       }
3217       Ty = TR.get();
3218     }
3219     Types.push_back(Ty);
3220 
3221     if (ExpectAndConsume(tok::colon)) {
3222       SkipUntil(tok::r_paren, StopAtSemi);
3223       return ExprError();
3224     }
3225 
3226     // FIXME: These expressions should be parsed in a potentially potentially
3227     // evaluated context.
3228     ExprResult ER(
3229         Actions.CorrectDelayedTyposInExpr(ParseAssignmentExpression()));
3230     if (ER.isInvalid()) {
3231       SkipUntil(tok::r_paren, StopAtSemi);
3232       return ExprError();
3233     }
3234     Exprs.push_back(ER.get());
3235   } while (TryConsumeToken(tok::comma));
3236 
3237   T.consumeClose();
3238   if (T.getCloseLocation().isInvalid())
3239     return ExprError();
3240 
3241   return Actions.ActOnGenericSelectionExpr(KeyLoc, DefaultLoc,
3242                                            T.getCloseLocation(),
3243                                            ControllingExpr.get(),
3244                                            Types, Exprs);
3245 }
3246 
3247 /// Parse A C++1z fold-expression after the opening paren and optional
3248 /// left-hand-side expression.
3249 ///
3250 /// \verbatim
3251 ///   fold-expression:
3252 ///       ( cast-expression fold-operator ... )
3253 ///       ( ... fold-operator cast-expression )
3254 ///       ( cast-expression fold-operator ... fold-operator cast-expression )
3255 ExprResult Parser::ParseFoldExpression(ExprResult LHS,
3256                                        BalancedDelimiterTracker &T) {
3257   if (LHS.isInvalid()) {
3258     T.skipToEnd();
3259     return true;
3260   }
3261 
3262   tok::TokenKind Kind = tok::unknown;
3263   SourceLocation FirstOpLoc;
3264   if (LHS.isUsable()) {
3265     Kind = Tok.getKind();
3266     assert(isFoldOperator(Kind) && "missing fold-operator");
3267     FirstOpLoc = ConsumeToken();
3268   }
3269 
3270   assert(Tok.is(tok::ellipsis) && "not a fold-expression");
3271   SourceLocation EllipsisLoc = ConsumeToken();
3272 
3273   ExprResult RHS;
3274   if (Tok.isNot(tok::r_paren)) {
3275     if (!isFoldOperator(Tok.getKind()))
3276       return Diag(Tok.getLocation(), diag::err_expected_fold_operator);
3277 
3278     if (Kind != tok::unknown && Tok.getKind() != Kind)
3279       Diag(Tok.getLocation(), diag::err_fold_operator_mismatch)
3280         << SourceRange(FirstOpLoc);
3281     Kind = Tok.getKind();
3282     ConsumeToken();
3283 
3284     RHS = ParseExpression();
3285     if (RHS.isInvalid()) {
3286       T.skipToEnd();
3287       return true;
3288     }
3289   }
3290 
3291   Diag(EllipsisLoc, getLangOpts().CPlusPlus17
3292                         ? diag::warn_cxx14_compat_fold_expression
3293                         : diag::ext_fold_expression);
3294 
3295   T.consumeClose();
3296   return Actions.ActOnCXXFoldExpr(getCurScope(), T.getOpenLocation(), LHS.get(),
3297                                   Kind, EllipsisLoc, RHS.get(),
3298                                   T.getCloseLocation());
3299 }
3300 
3301 /// ParseExpressionList - Used for C/C++ (argument-)expression-list.
3302 ///
3303 /// \verbatim
3304 ///       argument-expression-list:
3305 ///         assignment-expression
3306 ///         argument-expression-list , assignment-expression
3307 ///
3308 /// [C++] expression-list:
3309 /// [C++]   assignment-expression
3310 /// [C++]   expression-list , assignment-expression
3311 ///
3312 /// [C++0x] expression-list:
3313 /// [C++0x]   initializer-list
3314 ///
3315 /// [C++0x] initializer-list
3316 /// [C++0x]   initializer-clause ...[opt]
3317 /// [C++0x]   initializer-list , initializer-clause ...[opt]
3318 ///
3319 /// [C++0x] initializer-clause:
3320 /// [C++0x]   assignment-expression
3321 /// [C++0x]   braced-init-list
3322 /// \endverbatim
3323 bool Parser::ParseExpressionList(SmallVectorImpl<Expr *> &Exprs,
3324                                  SmallVectorImpl<SourceLocation> &CommaLocs,
3325                                  llvm::function_ref<void()> ExpressionStarts) {
3326   bool SawError = false;
3327   while (1) {
3328     if (ExpressionStarts)
3329       ExpressionStarts();
3330 
3331     ExprResult Expr;
3332     if (getLangOpts().CPlusPlus11 && Tok.is(tok::l_brace)) {
3333       Diag(Tok, diag::warn_cxx98_compat_generalized_initializer_lists);
3334       Expr = ParseBraceInitializer();
3335     } else
3336       Expr = ParseAssignmentExpression();
3337 
3338     if (Tok.is(tok::ellipsis))
3339       Expr = Actions.ActOnPackExpansion(Expr.get(), ConsumeToken());
3340     else if (Tok.is(tok::code_completion)) {
3341       // There's nothing to suggest in here as we parsed a full expression.
3342       // Instead fail and propogate the error since caller might have something
3343       // the suggest, e.g. signature help in function call. Note that this is
3344       // performed before pushing the \p Expr, so that signature help can report
3345       // current argument correctly.
3346       SawError = true;
3347       cutOffParsing();
3348       break;
3349     }
3350     if (Expr.isInvalid()) {
3351       SkipUntil(tok::comma, tok::r_paren, StopBeforeMatch);
3352       SawError = true;
3353     } else {
3354       Exprs.push_back(Expr.get());
3355     }
3356 
3357     if (Tok.isNot(tok::comma))
3358       break;
3359     // Move to the next argument, remember where the comma was.
3360     Token Comma = Tok;
3361     CommaLocs.push_back(ConsumeToken());
3362 
3363     checkPotentialAngleBracketDelimiter(Comma);
3364   }
3365   if (SawError) {
3366     // Ensure typos get diagnosed when errors were encountered while parsing the
3367     // expression list.
3368     for (auto &E : Exprs) {
3369       ExprResult Expr = Actions.CorrectDelayedTyposInExpr(E);
3370       if (Expr.isUsable()) E = Expr.get();
3371     }
3372   }
3373   return SawError;
3374 }
3375 
3376 /// ParseSimpleExpressionList - A simple comma-separated list of expressions,
3377 /// used for misc language extensions.
3378 ///
3379 /// \verbatim
3380 ///       simple-expression-list:
3381 ///         assignment-expression
3382 ///         simple-expression-list , assignment-expression
3383 /// \endverbatim
3384 bool
3385 Parser::ParseSimpleExpressionList(SmallVectorImpl<Expr*> &Exprs,
3386                                   SmallVectorImpl<SourceLocation> &CommaLocs) {
3387   while (1) {
3388     ExprResult Expr = ParseAssignmentExpression();
3389     if (Expr.isInvalid())
3390       return true;
3391 
3392     Exprs.push_back(Expr.get());
3393 
3394     if (Tok.isNot(tok::comma))
3395       return false;
3396 
3397     // Move to the next argument, remember where the comma was.
3398     Token Comma = Tok;
3399     CommaLocs.push_back(ConsumeToken());
3400 
3401     checkPotentialAngleBracketDelimiter(Comma);
3402   }
3403 }
3404 
3405 /// ParseBlockId - Parse a block-id, which roughly looks like int (int x).
3406 ///
3407 /// \verbatim
3408 /// [clang] block-id:
3409 /// [clang]   specifier-qualifier-list block-declarator
3410 /// \endverbatim
3411 void Parser::ParseBlockId(SourceLocation CaretLoc) {
3412   if (Tok.is(tok::code_completion)) {
3413     Actions.CodeCompleteOrdinaryName(getCurScope(), Sema::PCC_Type);
3414     return cutOffParsing();
3415   }
3416 
3417   // Parse the specifier-qualifier-list piece.
3418   DeclSpec DS(AttrFactory);
3419   ParseSpecifierQualifierList(DS);
3420 
3421   // Parse the block-declarator.
3422   Declarator DeclaratorInfo(DS, DeclaratorContext::BlockLiteral);
3423   DeclaratorInfo.setFunctionDefinitionKind(FunctionDefinitionKind::Definition);
3424   ParseDeclarator(DeclaratorInfo);
3425 
3426   MaybeParseGNUAttributes(DeclaratorInfo);
3427 
3428   // Inform sema that we are starting a block.
3429   Actions.ActOnBlockArguments(CaretLoc, DeclaratorInfo, getCurScope());
3430 }
3431 
3432 /// ParseBlockLiteralExpression - Parse a block literal, which roughly looks
3433 /// like ^(int x){ return x+1; }
3434 ///
3435 /// \verbatim
3436 ///         block-literal:
3437 /// [clang]   '^' block-args[opt] compound-statement
3438 /// [clang]   '^' block-id compound-statement
3439 /// [clang] block-args:
3440 /// [clang]   '(' parameter-list ')'
3441 /// \endverbatim
3442 ExprResult Parser::ParseBlockLiteralExpression() {
3443   assert(Tok.is(tok::caret) && "block literal starts with ^");
3444   SourceLocation CaretLoc = ConsumeToken();
3445 
3446   PrettyStackTraceLoc CrashInfo(PP.getSourceManager(), CaretLoc,
3447                                 "block literal parsing");
3448 
3449   // Enter a scope to hold everything within the block.  This includes the
3450   // argument decls, decls within the compound expression, etc.  This also
3451   // allows determining whether a variable reference inside the block is
3452   // within or outside of the block.
3453   ParseScope BlockScope(this, Scope::BlockScope | Scope::FnScope |
3454                                   Scope::CompoundStmtScope | Scope::DeclScope);
3455 
3456   // Inform sema that we are starting a block.
3457   Actions.ActOnBlockStart(CaretLoc, getCurScope());
3458 
3459   // Parse the return type if present.
3460   DeclSpec DS(AttrFactory);
3461   Declarator ParamInfo(DS, DeclaratorContext::BlockLiteral);
3462   ParamInfo.setFunctionDefinitionKind(FunctionDefinitionKind::Definition);
3463   // FIXME: Since the return type isn't actually parsed, it can't be used to
3464   // fill ParamInfo with an initial valid range, so do it manually.
3465   ParamInfo.SetSourceRange(SourceRange(Tok.getLocation(), Tok.getLocation()));
3466 
3467   // If this block has arguments, parse them.  There is no ambiguity here with
3468   // the expression case, because the expression case requires a parameter list.
3469   if (Tok.is(tok::l_paren)) {
3470     ParseParenDeclarator(ParamInfo);
3471     // Parse the pieces after the identifier as if we had "int(...)".
3472     // SetIdentifier sets the source range end, but in this case we're past
3473     // that location.
3474     SourceLocation Tmp = ParamInfo.getSourceRange().getEnd();
3475     ParamInfo.SetIdentifier(nullptr, CaretLoc);
3476     ParamInfo.SetRangeEnd(Tmp);
3477     if (ParamInfo.isInvalidType()) {
3478       // If there was an error parsing the arguments, they may have
3479       // tried to use ^(x+y) which requires an argument list.  Just
3480       // skip the whole block literal.
3481       Actions.ActOnBlockError(CaretLoc, getCurScope());
3482       return ExprError();
3483     }
3484 
3485     MaybeParseGNUAttributes(ParamInfo);
3486 
3487     // Inform sema that we are starting a block.
3488     Actions.ActOnBlockArguments(CaretLoc, ParamInfo, getCurScope());
3489   } else if (!Tok.is(tok::l_brace)) {
3490     ParseBlockId(CaretLoc);
3491   } else {
3492     // Otherwise, pretend we saw (void).
3493     SourceLocation NoLoc;
3494     ParamInfo.AddTypeInfo(
3495         DeclaratorChunk::getFunction(/*HasProto=*/true,
3496                                      /*IsAmbiguous=*/false,
3497                                      /*RParenLoc=*/NoLoc,
3498                                      /*ArgInfo=*/nullptr,
3499                                      /*NumParams=*/0,
3500                                      /*EllipsisLoc=*/NoLoc,
3501                                      /*RParenLoc=*/NoLoc,
3502                                      /*RefQualifierIsLvalueRef=*/true,
3503                                      /*RefQualifierLoc=*/NoLoc,
3504                                      /*MutableLoc=*/NoLoc, EST_None,
3505                                      /*ESpecRange=*/SourceRange(),
3506                                      /*Exceptions=*/nullptr,
3507                                      /*ExceptionRanges=*/nullptr,
3508                                      /*NumExceptions=*/0,
3509                                      /*NoexceptExpr=*/nullptr,
3510                                      /*ExceptionSpecTokens=*/nullptr,
3511                                      /*DeclsInPrototype=*/None, CaretLoc,
3512                                      CaretLoc, ParamInfo),
3513         CaretLoc);
3514 
3515     MaybeParseGNUAttributes(ParamInfo);
3516 
3517     // Inform sema that we are starting a block.
3518     Actions.ActOnBlockArguments(CaretLoc, ParamInfo, getCurScope());
3519   }
3520 
3521 
3522   ExprResult Result(true);
3523   if (!Tok.is(tok::l_brace)) {
3524     // Saw something like: ^expr
3525     Diag(Tok, diag::err_expected_expression);
3526     Actions.ActOnBlockError(CaretLoc, getCurScope());
3527     return ExprError();
3528   }
3529 
3530   StmtResult Stmt(ParseCompoundStatementBody());
3531   BlockScope.Exit();
3532   if (!Stmt.isInvalid())
3533     Result = Actions.ActOnBlockStmtExpr(CaretLoc, Stmt.get(), getCurScope());
3534   else
3535     Actions.ActOnBlockError(CaretLoc, getCurScope());
3536   return Result;
3537 }
3538 
3539 /// ParseObjCBoolLiteral - This handles the objective-c Boolean literals.
3540 ///
3541 ///         '__objc_yes'
3542 ///         '__objc_no'
3543 ExprResult Parser::ParseObjCBoolLiteral() {
3544   tok::TokenKind Kind = Tok.getKind();
3545   return Actions.ActOnObjCBoolLiteral(ConsumeToken(), Kind);
3546 }
3547 
3548 /// Validate availability spec list, emitting diagnostics if necessary. Returns
3549 /// true if invalid.
3550 static bool CheckAvailabilitySpecList(Parser &P,
3551                                       ArrayRef<AvailabilitySpec> AvailSpecs) {
3552   llvm::SmallSet<StringRef, 4> Platforms;
3553   bool HasOtherPlatformSpec = false;
3554   bool Valid = true;
3555   for (const auto &Spec : AvailSpecs) {
3556     if (Spec.isOtherPlatformSpec()) {
3557       if (HasOtherPlatformSpec) {
3558         P.Diag(Spec.getBeginLoc(), diag::err_availability_query_repeated_star);
3559         Valid = false;
3560       }
3561 
3562       HasOtherPlatformSpec = true;
3563       continue;
3564     }
3565 
3566     bool Inserted = Platforms.insert(Spec.getPlatform()).second;
3567     if (!Inserted) {
3568       // Rule out multiple version specs referring to the same platform.
3569       // For example, we emit an error for:
3570       // @available(macos 10.10, macos 10.11, *)
3571       StringRef Platform = Spec.getPlatform();
3572       P.Diag(Spec.getBeginLoc(), diag::err_availability_query_repeated_platform)
3573           << Spec.getEndLoc() << Platform;
3574       Valid = false;
3575     }
3576   }
3577 
3578   if (!HasOtherPlatformSpec) {
3579     SourceLocation InsertWildcardLoc = AvailSpecs.back().getEndLoc();
3580     P.Diag(InsertWildcardLoc, diag::err_availability_query_wildcard_required)
3581         << FixItHint::CreateInsertion(InsertWildcardLoc, ", *");
3582     return true;
3583   }
3584 
3585   return !Valid;
3586 }
3587 
3588 /// Parse availability query specification.
3589 ///
3590 ///  availability-spec:
3591 ///     '*'
3592 ///     identifier version-tuple
3593 Optional<AvailabilitySpec> Parser::ParseAvailabilitySpec() {
3594   if (Tok.is(tok::star)) {
3595     return AvailabilitySpec(ConsumeToken());
3596   } else {
3597     // Parse the platform name.
3598     if (Tok.is(tok::code_completion)) {
3599       Actions.CodeCompleteAvailabilityPlatformName();
3600       cutOffParsing();
3601       return None;
3602     }
3603     if (Tok.isNot(tok::identifier)) {
3604       Diag(Tok, diag::err_avail_query_expected_platform_name);
3605       return None;
3606     }
3607 
3608     IdentifierLoc *PlatformIdentifier = ParseIdentifierLoc();
3609     SourceRange VersionRange;
3610     VersionTuple Version = ParseVersionTuple(VersionRange);
3611 
3612     if (Version.empty())
3613       return None;
3614 
3615     StringRef GivenPlatform = PlatformIdentifier->Ident->getName();
3616     StringRef Platform =
3617         AvailabilityAttr::canonicalizePlatformName(GivenPlatform);
3618 
3619     if (AvailabilityAttr::getPrettyPlatformName(Platform).empty()) {
3620       Diag(PlatformIdentifier->Loc,
3621            diag::err_avail_query_unrecognized_platform_name)
3622           << GivenPlatform;
3623       return None;
3624     }
3625 
3626     return AvailabilitySpec(Version, Platform, PlatformIdentifier->Loc,
3627                             VersionRange.getEnd());
3628   }
3629 }
3630 
3631 ExprResult Parser::ParseAvailabilityCheckExpr(SourceLocation BeginLoc) {
3632   assert(Tok.is(tok::kw___builtin_available) ||
3633          Tok.isObjCAtKeyword(tok::objc_available));
3634 
3635   // Eat the available or __builtin_available.
3636   ConsumeToken();
3637 
3638   BalancedDelimiterTracker Parens(*this, tok::l_paren);
3639   if (Parens.expectAndConsume())
3640     return ExprError();
3641 
3642   SmallVector<AvailabilitySpec, 4> AvailSpecs;
3643   bool HasError = false;
3644   while (true) {
3645     Optional<AvailabilitySpec> Spec = ParseAvailabilitySpec();
3646     if (!Spec)
3647       HasError = true;
3648     else
3649       AvailSpecs.push_back(*Spec);
3650 
3651     if (!TryConsumeToken(tok::comma))
3652       break;
3653   }
3654 
3655   if (HasError) {
3656     SkipUntil(tok::r_paren, StopAtSemi);
3657     return ExprError();
3658   }
3659 
3660   CheckAvailabilitySpecList(*this, AvailSpecs);
3661 
3662   if (Parens.consumeClose())
3663     return ExprError();
3664 
3665   return Actions.ActOnObjCAvailabilityCheckExpr(AvailSpecs, BeginLoc,
3666                                                 Parens.getCloseLocation());
3667 }
3668