Part of PR15673: If a function template has a default argument in which
substitution failed, report that as a substitution failure rather than
pretending that there was no default argument.
The test cases in PR15673 have exposed some pre-existing poor diagnostics here.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@185604 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang/Sema/Sema.h b/include/clang/Sema/Sema.h
index 1b076a4..047cd89 100644
--- a/include/clang/Sema/Sema.h
+++ b/include/clang/Sema/Sema.h
@@ -5099,7 +5099,9 @@
SourceLocation TemplateLoc,
SourceLocation RAngleLoc,
Decl *Param,
- SmallVectorImpl<TemplateArgument> &Converted);
+ SmallVectorImpl<TemplateArgument>
+ &Converted,
+ bool &HasDefaultArg);
/// \brief Specifies the context in which a particular template
/// argument is being checked.
diff --git a/lib/Sema/SemaTemplate.cpp b/lib/Sema/SemaTemplate.cpp
index 2502db8..e6006b6 100644
--- a/lib/Sema/SemaTemplate.cpp
+++ b/lib/Sema/SemaTemplate.cpp
@@ -2703,11 +2703,16 @@
SourceLocation TemplateLoc,
SourceLocation RAngleLoc,
Decl *Param,
- SmallVectorImpl<TemplateArgument> &Converted) {
- if (TemplateTypeParmDecl *TypeParm = dyn_cast<TemplateTypeParmDecl>(Param)) {
+ SmallVectorImpl<TemplateArgument>
+ &Converted,
+ bool &HasDefaultArg) {
+ HasDefaultArg = false;
+
+ if (TemplateTypeParmDecl *TypeParm = dyn_cast<TemplateTypeParmDecl>(Param)) {
if (!TypeParm->hasDefaultArgument())
return TemplateArgumentLoc();
+ HasDefaultArg = true;
TypeSourceInfo *DI = SubstDefaultTemplateArgument(*this, Template,
TemplateLoc,
RAngleLoc,
@@ -2724,6 +2729,7 @@
if (!NonTypeParm->hasDefaultArgument())
return TemplateArgumentLoc();
+ HasDefaultArg = true;
ExprResult Arg = SubstDefaultTemplateArgument(*this, Template,
TemplateLoc,
RAngleLoc,
@@ -2741,7 +2747,7 @@
if (!TempTempParm->hasDefaultArgument())
return TemplateArgumentLoc();
-
+ HasDefaultArg = true;
NestedNameSpecifierLoc QualifierLoc;
TemplateName TName = SubstDefaultTemplateArgument(*this, Template,
TemplateLoc,
diff --git a/lib/Sema/SemaTemplateDeduction.cpp b/lib/Sema/SemaTemplateDeduction.cpp
index 8efc7a0..0fd29ea 100644
--- a/lib/Sema/SemaTemplateDeduction.cpp
+++ b/lib/Sema/SemaTemplateDeduction.cpp
@@ -2704,18 +2704,21 @@
}
// Substitute into the default template argument, if available.
+ bool HasDefaultArg = false;
TemplateArgumentLoc DefArg
= SubstDefaultTemplateArgumentIfAvailable(FunctionTemplate,
FunctionTemplate->getLocation(),
FunctionTemplate->getSourceRange().getEnd(),
Param,
- Builder);
+ Builder, HasDefaultArg);
// If there was no default argument, deduction is incomplete.
if (DefArg.getArgument().isNull()) {
Info.Param = makeTemplateParameter(
const_cast<NamedDecl *>(TemplateParams->getParam(I)));
- return TDK_Incomplete;
+ Info.reset(TemplateArgumentList::CreateCopy(Context, Builder.data(),
+ Builder.size()));
+ return HasDefaultArg ? TDK_SubstitutionFailure : TDK_Incomplete;
}
// Check whether we can actually use the default argument.
diff --git a/test/SemaTemplate/overload-candidates.cpp b/test/SemaTemplate/overload-candidates.cpp
index ad65397..544d897 100644
--- a/test/SemaTemplate/overload-candidates.cpp
+++ b/test/SemaTemplate/overload-candidates.cpp
@@ -79,3 +79,48 @@
void test() {
foo(NS1::array<int>()); // expected-error{{no matching function for call to 'foo'}}
}
+
+namespace std {
+ template<bool, typename = void> struct enable_if {};
+ template<typename T> struct enable_if<true, T> { typedef T type; };
+
+ template<typename T, T V> struct integral_constant { static const T value = V; };
+ typedef integral_constant<bool, false> false_type;
+ typedef integral_constant<bool, true> true_type;
+};
+
+namespace PR15673 {
+ template<typename T>
+ struct a_trait : std::false_type {};
+
+ template<typename T,
+ typename Requires = typename std::enable_if<a_trait<T>::value>::type> // expected-warning {{C++11 extension}}
+ // expected-note@-1 {{candidate template ignored: disabled by 'enable_if' [with T = int]}}
+ void foo() {}
+ void bar() { foo<int>(); } // expected-error {{no matching function for call to 'foo'}}
+
+
+ template<typename T>
+ struct some_trait : std::false_type {};
+
+ // FIXME: It would be nice to tunnel the 'disabled by enable_if' diagnostic through here.
+ template<typename T>
+ struct a_pony : std::enable_if<some_trait<T>::value> {};
+
+ template<typename T,
+ typename Requires = typename a_pony<T>::type> // expected-warning {{C++11 extension}}
+ // FIXME: The source location here is poor.
+ void baz() { } // expected-note {{candidate template ignored: substitution failure [with T = int]: no type named 'type' in 'PR15673::a_pony<int>'}}
+ void quux() { baz<int>(); } // expected-error {{no matching function for call to 'baz'}}
+
+
+ // FIXME: This note doesn't make it clear which candidate we rejected.
+ template <typename T>
+ using unicorns = typename std::enable_if<some_trait<T>::value>::type; // expected-warning {{C++11 extension}}
+ // expected-note@-1 {{candidate template ignored: disabled by 'enable_if' [with T = int]}}
+
+ template<typename T,
+ typename Requires = unicorns<T> > // expected-warning {{C++11 extension}}
+ void wibble() {}
+ void wobble() { wibble<int>(); } // expected-error {{no matching function for call to 'wibble'}}
+}
