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Handle a difference in lambda return type deduction between C++11 and C++1y: if 

no return type is specified, C++11 will deduce a cv-qualified return type in
some cases, but C++1y never will.

llvm-svn: 187275
This commit is contained in:
Richard Smith 2013-07-26 23:45:07 +00:00
parent 3cf7eb50a9
commit 1836e60023
3 changed files with 27 additions and 4 deletions
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10
clang/lib/Sema/SemaStmt.cpp
View File

@ -2376,9 +2376,15 @@ Sema::ActOnCapScopeReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) {
return StmtError();
RetValExp = Result.take();
if (!CurContext->isDependentContext())
if (!CurContext->isDependentContext()) {
FnRetType = RetValExp->getType();
else
// In C++11, we take the type of the expression after decay and
// lvalue-to-rvalue conversion, so a class type can be cv-qualified.
// In C++1y, we perform template argument deduction as if the return
// type were 'auto', so an implicit return type is never cv-qualified.
if (getLangOpts().CPlusPlus1y && FnRetType.hasQualifiers())
FnRetType = FnRetType.getUnqualifiedType();
} else
FnRetType = CurCap->ReturnType = Context.DependentTy;
} else {
if (RetValExp) {

5
clang/test/CXX/expr/expr.prim/expr.prim.lambda/p4.cpp
View File

@ -39,7 +39,10 @@ X infer_X_return_type_fail(X x) {
if (y > 0)
return X();
else
return x; // expected-error{{return type 'const X' must match previous return type 'X' when lambda expression has unspecified explicit return type}}
return x;
#if __cplusplus <= 201103L
// expected-error@-2 {{return type 'const X' must match previous return type 'X' when lambda expression has unspecified explicit return type}}
#endif
}(5);
}

16
clang/test/SemaCXX/lambda-expressions.cpp
View File

@ -1,4 +1,5 @@
// RUN: %clang_cc1 -std=c++0x -Wno-unused-value -fsyntax-only -verify -fblocks %s
// RUN: %clang_cc1 -std=c++11 -Wno-unused-value -fsyntax-only -verify -fblocks %s
// RUN: %clang_cc1 -std=c++1y -Wno-unused-value -fsyntax-only -verify -fblocks %s
namespace std { class type_info; };
@ -251,3 +252,16 @@ namespace PR16708 {
return 0;
};
}
namespace TypeDeduction {
struct S {};
void f() {
const S s {};
S &&t = [&] { return s; } ();
#if __cplusplus <= 201103L
// expected-error@-2 {{drops qualifiers}}
#else
S &&u = [&] () -> auto { return s; } ();
#endif
}
}