When some template parameters of a class template partial
specialization cannot be deduced, produce a warning noting that the
affected class template partial specialization will never be used.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@73274 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaTemplate.cpp b/lib/Sema/SemaTemplate.cpp
index 54c61f6..78c1a9a 100644
--- a/lib/Sema/SemaTemplate.cpp
+++ b/lib/Sema/SemaTemplate.cpp
@@ -2328,8 +2328,6 @@
Specialization->setLocation(TemplateNameLoc);
PrevDecl = 0;
} else if (isPartialSpecialization) {
- // FIXME: extra checking for partial specializations
-
// Create a new class template partial specialization declaration node.
TemplateParameterList *TemplateParams
= static_cast<TemplateParameterList*>(*TemplateParameterLists.get());
@@ -2351,6 +2349,38 @@
ClassTemplate->getPartialSpecializations().InsertNode(Partial, InsertPos);
}
Specialization = Partial;
+
+ // Check that all of the template parameters of the class template
+ // partial specialization are deducible from the template
+ // arguments. If not, this class template partial specialization
+ // will never be used.
+ llvm::SmallVector<bool, 8> DeducibleParams;
+ DeducibleParams.resize(TemplateParams->size());
+ MarkDeducedTemplateParameters(Partial->getTemplateArgs(), DeducibleParams);
+ unsigned NumNonDeducible = 0;
+ for (unsigned I = 0, N = DeducibleParams.size(); I != N; ++I)
+ if (!DeducibleParams[I])
+ ++NumNonDeducible;
+
+ if (NumNonDeducible) {
+ Diag(TemplateNameLoc, diag::warn_partial_specs_not_deducible)
+ << (NumNonDeducible > 1)
+ << SourceRange(TemplateNameLoc, RAngleLoc);
+ for (unsigned I = 0, N = DeducibleParams.size(); I != N; ++I) {
+ if (!DeducibleParams[I]) {
+ NamedDecl *Param = cast<NamedDecl>(TemplateParams->getParam(I));
+ if (Param->getDeclName())
+ Diag(Param->getLocation(),
+ diag::note_partial_spec_unused_parameter)
+ << Param->getDeclName();
+ else
+ Diag(Param->getLocation(),
+ diag::note_partial_spec_unused_parameter)
+ << std::string("<anonymous>");
+ }
+ }
+ }
+
} else {
// Create a new class template specialization declaration node for
// this explicit specialization.