llvm-project/clang/test/AST/foreachtemplatized.mm

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[ast] Do not auto-initialize Objective-C for-loop variables in Objective-C++ in templatized code under ARC The AST for the fragment ``` @interface I @end template <typename> void decode(I *p) { for (I *k in p) {} } void decode(I *p) { decode<int>(p); } ``` differs heavily when templatized and non-templatized: ``` |-FunctionTemplateDecl 0x7fbfe0863940 <line:4:1, line:7:1> line:5:6 decode | |-TemplateTypeParmDecl 0x7fbfe0863690 <line:4:11> col:11 typename depth 0 index 0 | |-FunctionDecl 0x7fbfe08638a0 <line:5:1, line:7:1> line:5:6 decode 'void (I *__strong)' | | |-ParmVarDecl 0x7fbfe08637a0 <col:13, col:16> col:16 referenced p 'I *__strong' | | `-CompoundStmt 0x7fbfe0863b88 <col:19, line:7:1> | |   `-ObjCForCollectionStmt 0x7fbfe0863b50 <line:6:3, col:20> | |     |-DeclStmt 0x7fbfe0863a50 <col:8, col:13> | |     | `-VarDecl 0x7fbfe08639f0 <col:8, col:11> col:11 k 'I *const __strong' | |     |-ImplicitCastExpr 0x7fbfe0863a90 <col:16> 'I *' <LValueToRValue> | |     | `-DeclRefExpr 0x7fbfe0863a68 <col:16> 'I *__strong' lvalue ParmVar 0x7fbfe08637a0 'p' 'I *__strong' | |     `-CompoundStmt 0x7fbfe0863b78 <col:19, col:20> | `-FunctionDecl 0x7fbfe0863f80 <line:5:1, line:7:1> line:5:6 used decode 'void (I *__strong)' |   |-TemplateArgument type 'int' |   |-ParmVarDecl 0x7fbfe0863ef8 <col:13, col:16> col:16 used p 'I *__strong' |   `-CompoundStmt 0x7fbfe0890cf0 <col:19, line:7:1> |     `-ObjCForCollectionStmt 0x7fbfe0890cc8 <line:6:3, col:20> |       |-DeclStmt 0x7fbfe0890c70 <col:8, col:13> |       | `-VarDecl 0x7fbfe0890c00 <col:8, col:11> col:11 k 'I *__strong' callinit |       |   `-ImplicitValueInitExpr 0x7fbfe0890c60 <<invalid sloc>> 'I *__strong' |       |-ImplicitCastExpr 0x7fbfe0890cb0 <col:16> 'I *' <LValueToRValue> |       | `-DeclRefExpr 0x7fbfe0890c88 <col:16> 'I *__strong' lvalue ParmVar 0x7fbfe0863ef8 'p' 'I *__strong' |       `-CompoundStmt 0x7fbfe0863b78 <col:19, col:20> ``` Note how in the instantiated version ImplicitValueInitExpr unexpectedly appears. While objects are auto-initialized under ARC, it does not make sense to have an initializer for a for-loop variable, and it makes even less sense to have such a different AST for instantiated and non-instantiated version. Digging deeper, I have found that there are two separate Sema* files for dealing with templates and for dealing with non-templatized code. In a non-templatized version, an initialization was performed only for variables which are not loop variables for an Objective-C loop and not variables for a C++ for-in loop: ```   if (FRI && (Tok.is(tok::colon) || isTokIdentifier_in())) {     bool IsForRangeLoop = false;     if (TryConsumeToken(tok::colon, FRI->ColonLoc)) {       IsForRangeLoop = true;       if (Tok.is(tok::l_brace))         FRI->RangeExpr = ParseBraceInitializer();       else         FRI->RangeExpr = ParseExpression();     }     Decl *ThisDecl = Actions.ActOnDeclarator(getCurScope(), D);     if (IsForRangeLoop)       Actions.ActOnCXXForRangeDecl(ThisDecl);     Actions.FinalizeDeclaration(ThisDecl);     D.complete(ThisDecl);     return Actions.FinalizeDeclaratorGroup(getCurScope(), DS, ThisDecl);   }   SmallVector<Decl *, 8> DeclsInGroup;   Decl *FirstDecl = ParseDeclarationAfterDeclaratorAndAttributes(       D, ParsedTemplateInfo(), FRI); ``` However the code in SemaTemplateInstantiateDecl was inconsistent, guarding only against C++ for-in loops. rdar://38391075 Differential Revision: https://reviews.llvm.org/D44989 llvm-svn: 328749
2018-03-29 08:56:24 +08:00
// RUN: %clang_cc1 -fsyntax-only -fobjc-arc -Wno-objc-root-class -std=c++11 -ast-dump %s | FileCheck %s
// CHECK-NOT: ImplicitValueInitExpr
@interface I
@end
template <typename T>
void decode(I *p) {
for (I *k in p) {}
}
void decode(I *p) {
decode<int>(p);
}