Fix regression introduced by r279164: only pass definitions as the PatternDef

to DiagnoseUninstantiableTemplate, teach hasVisibleDefinition to correctly
determine whether a function definition is visible, and mark both the function
and the template as visible when merging function template definitions to
provide hasVisibleDefinition with the relevant information.

The change to always pass the right declaration as the PatternDef to
DiagnoseUninstantiableTemplate also caused those checks to happen before other
diagnostics in InstantiateFunctionDefinition, giving worse diagnostics for the
same situations, so I sunk the relevant diagnostics into
DiagnoseUninstantiableTemplate. Those parts of this patch are based on changes
in reviews.llvm.org/D23492 by Vassil Vassilev.

llvm-svn: 279486

1 files changed, 23 insertions, 10 deletions

diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
index ede1c5bcc64..6241f524af2 100644
--- a/clang/lib/Sema/SemaTemplate.cpp
+++ b/clang/lib/Sema/SemaTemplate.cpp
@@ -487,8 +487,6 @@ bool Sema::DiagnoseUninstantiableTemplate(SourceLocation PointOfInstantiation,
   QualType InstantiationTy;
   if (TagDecl *TD = dyn_cast<TagDecl>(Instantiation))
     InstantiationTy = Context.getTypeDeclType(TD);
-  else
-    InstantiationTy = cast<FunctionDecl>(Instantiation)->getType();
   if (!Complain || (PatternDef && PatternDef->isInvalidDecl())) {
     // Say nothing
   } else if (PatternDef) {
@@ -500,15 +498,30 @@ bool Sema::DiagnoseUninstantiableTemplate(SourceLocation PointOfInstantiation,
     // we're lexically inside it.
     Instantiation->setInvalidDecl();
   } else if (InstantiatedFromMember) {
-    Diag(PointOfInstantiation,
-         diag::err_implicit_instantiate_member_undefined)
-      << InstantiationTy;
-    Diag(Pattern->getLocation(), diag::note_member_declared_at);
+    if (isa<FunctionDecl>(Instantiation)) {
+      Diag(PointOfInstantiation,
+           diag::err_explicit_instantiation_undefined_member)
+        << 1 << Instantiation->getDeclName() << Instantiation->getDeclContext();
+    } else {
+      Diag(PointOfInstantiation,
+           diag::err_implicit_instantiate_member_undefined)
+        << InstantiationTy;
+    }
+    Diag(Pattern->getLocation(), isa<FunctionDecl>(Instantiation)
+                                     ? diag::note_explicit_instantiation_here
+                                     : diag::note_member_declared_at);
   } else {
-    Diag(PointOfInstantiation, diag::err_template_instantiate_undefined)
-      << (TSK != TSK_ImplicitInstantiation)
-      << InstantiationTy;
-    Diag(Pattern->getLocation(), diag::note_template_decl_here);
+    if (isa<FunctionDecl>(Instantiation))
+      Diag(PointOfInstantiation,
+           diag::err_explicit_instantiation_undefined_func_template)
+        << Pattern;
+    else
+      Diag(PointOfInstantiation, diag::err_template_instantiate_undefined)
+        << (TSK != TSK_ImplicitInstantiation)
+        << InstantiationTy;
+    Diag(Pattern->getLocation(), isa<FunctionDecl>(Instantiation)
+                                     ? diag::note_explicit_instantiation_here
+                                     : diag::note_template_decl_here);
   }
 
   // In general, Instantiation isn't marked invalid to get more than one