Author: rsmith
Date: Fri Feb 10 13:49:50 2017
New Revision: 294773
URL: http://llvm.org/viewvc/llvm-project?rev=294773&view=rev
Log:
[c++1z] Disallow deduction guides with deduced types that don't syntactically
match the template being deduced.
Modified:
cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
cfe/trunk/lib/Sema/SemaDeclCXX.cpp
cfe/trunk/test/CXX/temp/temp.deduct.guide/p3.cpp
Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=294773&r1=294772&r2=294773&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Fri Feb 10 13:49:50
2017
@@ -1981,6 +1981,9 @@ def err_deduced_class_template_explicit
"%select{constructor|deduction guide}1 for copy-list-initialization">;
def err_deduction_guide_no_trailing_return_type : Error<
"deduction guide declaration without trailing return type">;
+def err_deduction_guide_bad_trailing_return_type : Error<
+ "deduced type %1 of deduction guide is not %select{|written as }2"
+ "a specialization of template %0">;
def err_deduction_guide_with_complex_decl : Error<
"cannot specify any part of a return type in the "
"declaration of a deduction guide">;
Modified: cfe/trunk/lib/Sema/SemaDeclCXX.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDeclCXX.cpp?rev=294773&r1=294772&r2=294773&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaDeclCXX.cpp (original)
+++ cfe/trunk/lib/Sema/SemaDeclCXX.cpp Fri Feb 10 13:49:50 2017
@@ -8192,12 +8192,46 @@ void Sema::CheckDeductionGuideDeclarator
diag::err_deduction_guide_no_trailing_return_type);
break;
}
+
+ // Check that the return type is written as a specialization of
+ // the template specified as the deduction-guide's name.
+ ParsedType TrailingReturnType = Chunk.Fun.getTrailingReturnType();
+ TemplateName GuidedTemplate = D.getName().TemplateName.get().get();
+ TypeSourceInfo *TSI = nullptr;
+ QualType RetTy = GetTypeFromParser(TrailingReturnType, &TSI);
+ assert(TSI && "deduction guide has valid type but invalid return type?");
+ bool AcceptableReturnType = false;
+ bool MightInstantiateToSpecialization = false;
+ if (auto RetTST =
+ TSI->getTypeLoc().getAs<TemplateSpecializationTypeLoc>()) {
+ TemplateName SpecifiedName = RetTST.getTypePtr()->getTemplateName();
+ bool TemplateMatches =
+ Context.hasSameTemplateName(SpecifiedName, GuidedTemplate);
+ if (SpecifiedName.getKind() == TemplateName::Template && TemplateMatches)
+ AcceptableReturnType = true;
+ else {
+ // This could still instantiate to the right type, unless we know it
+ // names the wrong class template.
+ auto *TD = SpecifiedName.getAsTemplateDecl();
+ MightInstantiateToSpecialization = !(TD && isa<ClassTemplateDecl>(TD)
&&
+ !TemplateMatches);
+ }
+ } else if (!RetTy.hasQualifiers() && RetTy->isDependentType()) {
+ MightInstantiateToSpecialization = true;
+ }
+
+ if (!AcceptableReturnType) {
+ Diag(TSI->getTypeLoc().getLocStart(),
+ diag::err_deduction_guide_bad_trailing_return_type)
+ << GuidedTemplate << TSI->getType() << MightInstantiateToSpecialization
+ << TSI->getTypeLoc().getSourceRange();
+ }
+
+ // Keep going to check that we don't have any inner declarator pieces (we
+ // could still have a function returning a pointer to a function).
FoundFunction = true;
}
- // FIXME: Check that the return type can instantiate to a specialization of
- // the template specified as the deduction-guide's name.
-
if (D.isFunctionDefinition())
Diag(D.getIdentifierLoc(), diag::err_deduction_guide_defines_function);
}
Modified: cfe/trunk/test/CXX/temp/temp.deduct.guide/p3.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CXX/temp/temp.deduct.guide/p3.cpp?rev=294773&r1=294772&r2=294773&view=diff
==============================================================================
--- cfe/trunk/test/CXX/temp/temp.deduct.guide/p3.cpp (original)
+++ cfe/trunk/test/CXX/temp/temp.deduct.guide/p3.cpp Fri Feb 10 13:49:50 2017
@@ -32,11 +32,9 @@ template<template<typename> typename TT>
TT(int) -> TT<int>; // expected-error 2{{cannot specify deduction guide for
template template parameter 'TT'}} expected-error {{requires an identifier}}
};
-// FIXME: Even if the DR is applied as we hope, we should still warn if the
-// trailing-return-type can obviously never produce a specialization of the
-// named template.
-A(int) -> int;
-template<typename T> A(T) -> T*;
+A(int) -> int; // expected-error {{deduced type 'int' of deduction guide is
not a specialization of template 'A'}}
+template<typename T> A(T) -> B<T>; // expected-error {{deduced type 'B<T>'
(aka 'A<type-parameter-0-0>') of deduction guide is not written as a
specialization of template 'A'}}
+template<typename T> A(T*) -> const A<T>; // expected-error {{deduced type
'const A<T>' of deduction guide is not a specialization of template 'A'}}
// A deduction-guide shall be declared in the same scope as the corresponding
// class template.
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