Revert r279486 "Fix regression introduced by r279164"

Build bots seem unhappy and as Richard was leaving he asked me to revert
this for him. Doing so.

llvm-svn: 279500

4 files changed, 59 insertions, 59 deletions

diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 9122030e16d..ca4de55fb51 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -11274,8 +11274,9 @@ Sema::CheckForFunctionRedefinition(FunctionDecl *FD,
     SkipBody->ShouldSkip = true;
     if (auto *TD = Definition->getDescribedFunctionTemplate())
       makeMergedDefinitionVisible(TD, FD->getLocation());
-    makeMergedDefinitionVisible(const_cast<FunctionDecl*>(Definition),
-                                FD->getLocation());
+    else
+      makeMergedDefinitionVisible(const_cast<FunctionDecl*>(Definition),
+                                  FD->getLocation());
     return;
   }
 
diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
index 6241f524af2..ede1c5bcc64 100644
--- a/clang/lib/Sema/SemaTemplate.cpp
+++ b/clang/lib/Sema/SemaTemplate.cpp
@@ -487,6 +487,8 @@ 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) {
@@ -498,30 +500,15 @@ bool Sema::DiagnoseUninstantiableTemplate(SourceLocation PointOfInstantiation,
     // we're lexically inside it.
     Instantiation->setInvalidDecl();
   } else if (InstantiatedFromMember) {
-    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);
+    Diag(PointOfInstantiation,
+         diag::err_implicit_instantiate_member_undefined)
+      << InstantiationTy;
+    Diag(Pattern->getLocation(), diag::note_member_declared_at);
   } else {
-    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);
+    Diag(PointOfInstantiation, diag::err_template_instantiate_undefined)
+      << (TSK != TSK_ImplicitInstantiation)
+      << InstantiationTy;
+    Diag(Pattern->getLocation(), diag::note_template_decl_here);
   }
 
   // In general, Instantiation isn't marked invalid to get more than one
diff --git a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
index 75d7f70a636..3f4a0f6f39a 100644
--- a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -3554,38 +3554,23 @@ void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
   const FunctionDecl *PatternDecl = Function->getTemplateInstantiationPattern();
   assert(PatternDecl && "instantiating a non-template");
 
-  const FunctionDecl *PatternDef = PatternDecl->getDefinition();
-  Stmt *Pattern = PatternDef->getBody(PatternDef);
-  if (PatternDef)
-    PatternDecl = PatternDef;
+  Stmt *Pattern = PatternDecl->getBody(PatternDecl);
+  assert(PatternDecl && "template definition is not a template");
+  if (!Pattern) {
+    // Try to find a defaulted definition
+    PatternDecl->isDefined(PatternDecl);
+  }
+  assert(PatternDecl && "template definition is not a template");
 
   // FIXME: We need to track the instantiation stack in order to know which
   // definitions should be visible within this instantiation.
   if (DiagnoseUninstantiableTemplate(PointOfInstantiation, Function,
                                 Function->getInstantiatedFromMemberFunction(),
-                                     PatternDecl, PatternDef, TSK,
-                                     /*Complain*/DefinitionRequired)) {
-    if (DefinitionRequired)
-      Function->setInvalidDecl();
-    else if (TSK == TSK_ExplicitInstantiationDefinition) {
-      // Try again at the end of the translation unit (at which point a
-      // definition will be required).
-      assert(!Recursive);
-      PendingInstantiations.push_back(
-        std::make_pair(Function, PointOfInstantiation));
-    } else if (TSK == TSK_ImplicitInstantiation) {
-      if (AtEndOfTU && !getDiagnostics().hasErrorOccurred()) {
-        Diag(PointOfInstantiation, diag::warn_func_template_missing)
-          << Function;
-        Diag(PatternDecl->getLocation(), diag::note_forward_template_decl);
-        if (getLangOpts().CPlusPlus11)
-          Diag(PointOfInstantiation, diag::note_inst_declaration_hint)
-            << Function;
-      }
-    }
+                                     PatternDecl, PatternDecl, TSK,
+                                     /*Complain*/DefinitionRequired))
+     return;
+
 
-    return;
-  }
 
   // Postpone late parsed template instantiations.
   if (PatternDecl->isLateTemplateParsed() &&
@@ -3619,9 +3604,40 @@ void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
     Pattern = PatternDecl->getBody(PatternDecl);
   }
 
-  // Note, we should never try to instantiate a deleted function template.
-  assert((Pattern || PatternDecl->isDefaulted()) &&
-         "unexpected kind of function template definition");
+  // FIXME: Check if we could sink these diagnostics in
+  // DiagnoseUninstantiableTemplate.
+  if (!Pattern && !PatternDecl->isDefaulted()) {
+    if (DefinitionRequired) {
+      if (Function->getPrimaryTemplate())
+        Diag(PointOfInstantiation,
+             diag::err_explicit_instantiation_undefined_func_template)
+          << Function->getPrimaryTemplate();
+      else
+        Diag(PointOfInstantiation,
+             diag::err_explicit_instantiation_undefined_member)
+          << 1 << Function->getDeclName() << Function->getDeclContext();
+
+      if (PatternDecl)
+        Diag(PatternDecl->getLocation(),
+             diag::note_explicit_instantiation_here);
+      Function->setInvalidDecl();
+    } else if (TSK == TSK_ExplicitInstantiationDefinition) {
+      assert(!Recursive);
+      PendingInstantiations.push_back(
+        std::make_pair(Function, PointOfInstantiation));
+    } else if (TSK == TSK_ImplicitInstantiation) {
+      if (AtEndOfTU && !getDiagnostics().hasErrorOccurred()) {
+        Diag(PointOfInstantiation, diag::warn_func_template_missing)
+          << Function;
+        Diag(PatternDecl->getLocation(), diag::note_forward_template_decl);
+        if (getLangOpts().CPlusPlus11)
+          Diag(PointOfInstantiation, diag::note_inst_declaration_hint)
+            << Function;
+      }
+    }
+
+    return;
+  }
 
   // C++1y [temp.explicit]p10:
   //   Except for inline functions, declarations with types deduced from their
diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index 8a49f6120cf..091a4e34e19 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -6890,10 +6890,6 @@ bool Sema::hasVisibleDefinition(NamedDecl *D, NamedDecl **Suggested,
       return false;
     }
     D = ED->getDefinition();
-  } else if (auto *FD = dyn_cast<FunctionDecl>(D)) {
-    if (auto *Pattern = FD->getTemplateInstantiationPattern())
-      FD = Pattern;
-    D = FD->getDefinition();
   }
   assert(D && "missing definition for pattern of instantiated definition");
 
@@ -6901,7 +6897,7 @@ bool Sema::hasVisibleDefinition(NamedDecl *D, NamedDecl **Suggested,
   if (isVisible(D))
     return true;
 
-  // The external source may have additional definitions of this entity that are
+  // The external source may have additional definitions of this type that are
   // visible, so complete the redeclaration chain now and ask again.
   if (auto *Source = Context.getExternalSource()) {
     Source->CompleteRedeclChain(D);