Add CheckCallReturnType and start using it for regular call expressions. This will improve error messages. For

struct B;

B f();

void g() {
f();
}

We now get

t.cpp:6:3: error: calling 'f' with incomplete return type 'struct B'
  f();
  ^~~
t.cpp:3:3: note: 'f' declared here
B f();
  ^
t.cpp:1:8: note: forward declaration of 'struct B'
struct B;
       ^

llvm-svn: 83692

4 files changed, 47 insertions, 11 deletions

diff --git a/clang/lib/Sema/Sema.h b/clang/lib/Sema/Sema.h
index 33d7468787d..6c9466f8639 100644
--- a/clang/lib/Sema/Sema.h
+++ b/clang/lib/Sema/Sema.h
@@ -493,7 +493,10 @@ public:
   virtual TypeResult ActOnTypeName(Scope *S, Declarator &D);
 
   bool RequireCompleteType(SourceLocation Loc, QualType T,
-                           const PartialDiagnostic &PD);
+                           const PartialDiagnostic &PD,
+                           std::pair<SourceLocation,
+                                     PartialDiagnostic> Note =
+                            std::make_pair(SourceLocation(), PDiag()));
 
   QualType getQualifiedNameType(const CXXScopeSpec &SS, QualType T);
 
@@ -959,6 +962,12 @@ public:
   OwningExprResult BuildOverloadedArrowExpr(Scope *S, ExprArg Base,
                                             SourceLocation OpLoc);
 
+  /// CheckCallReturnType - Checks that a call expression's return type is
+  /// complete. Returns true on failure. The location passed in is the location
+  /// that best represents the call.
+  bool CheckCallReturnType(QualType ReturnType, SourceLocation Loc,
+                           CallExpr *CE, FunctionDecl *FD);
+                           
   /// Helpers for dealing with blocks and functions.
   void CheckFallThroughForFunctionDef(Decl *D, Stmt *Body);
   void CheckFallThroughForBlock(QualType BlockTy, Stmt *Body);
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index b4384b11fdc..9831fba3190 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -3013,11 +3013,9 @@ Sema::ActOnCallExpr(Scope *S, ExprArg fn, SourceLocation LParenLoc,
       << Fn->getType() << Fn->getSourceRange());
 
   // Check for a valid return type
-  if (!FuncT->getResultType()->isVoidType() &&
-      RequireCompleteType(Fn->getSourceRange().getBegin(),
-                          FuncT->getResultType(),
-                          PDiag(diag::err_call_incomplete_return)
-                            << TheCall->getSourceRange()))
+  if (CheckCallReturnType(FuncT->getResultType(), 
+                          Fn->getSourceRange().getBegin(), TheCall.get(),
+                          FDecl))
     return ExprError();
 
   // We know the result type of the call, set it.
@@ -6223,3 +6221,26 @@ void Sema::MarkDeclarationReferenced(SourceLocation Loc, Decl *D) {
     return;
   }
 }
+
+bool Sema::CheckCallReturnType(QualType ReturnType, SourceLocation Loc,
+                               CallExpr *CE, FunctionDecl *FD) {
+  if (ReturnType->isVoidType() || !ReturnType->isIncompleteType())
+    return false;
+
+  PartialDiagnostic Note =
+    FD ? PDiag(diag::note_function_with_incomplete_return_type_declared_here)
+    << FD->getDeclName() : PDiag();
+  SourceLocation NoteLoc = FD ? FD->getLocation() : SourceLocation();
+  
+  if (RequireCompleteType(Loc, ReturnType,
+                          FD ? 
+                          PDiag(diag::err_call_function_incomplete_return)
+                            << CE->getSourceRange() << FD->getDeclName() :
+                          PDiag(diag::err_call_incomplete_return) 
+                            << CE->getSourceRange(),
+                          std::make_pair(NoteLoc, Note)))
+    return true;
+
+  return false;
+}
+
diff --git a/clang/lib/Sema/SemaOverload.cpp b/clang/lib/Sema/SemaOverload.cpp
index 04568a5d3af..9615a3cf57d 100644
--- a/clang/lib/Sema/SemaOverload.cpp
+++ b/clang/lib/Sema/SemaOverload.cpp
@@ -2759,7 +2759,7 @@ void Sema::AddMemberOperatorCandidates(OverloadedOperatorKind Op,
   //        empty.
   if (const RecordType *T1Rec = T1->getAs<RecordType>()) {
     // Complete the type if it can be completed. Otherwise, we're done.
-    if (RequireCompleteType(OpLoc, T1, PartialDiagnostic(0)))
+    if (RequireCompleteType(OpLoc, T1, PDiag()))
       return;
 
     LookupResult Operators;
@@ -4219,10 +4219,10 @@ Sema::ResolveAddressOfOverloadedFunction(Expr *From, QualType ToType,
                                                          Matches.end());
     return getMostSpecialized(TemplateMatches.data(), TemplateMatches.size(), 
                               TPOC_Other, From->getLocStart(),
-                              PartialDiagnostic(0),
-                            PartialDiagnostic(diag::err_addr_ovl_ambiguous)
+                              PDiag(),
+                              PDiag(diag::err_addr_ovl_ambiguous)
                               << TemplateMatches[0]->getDeclName(), 
-                       PartialDiagnostic(diag::err_ovl_template_candidate));
+                              PDiag(diag::err_ovl_template_candidate));
   }
 
   //   [...] any function template specializations in the set are
diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index da72197f0ca..67677120858 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -1820,7 +1820,9 @@ void Sema::ProcessTypeAttributeList(QualType &Result, const AttributeList *AL) {
 /// @returns @c true if @p T is incomplete and a diagnostic was emitted,
 /// @c false otherwise.
 bool Sema::RequireCompleteType(SourceLocation Loc, QualType T,
-                               const PartialDiagnostic &PD) {
+                               const PartialDiagnostic &PD,
+                               std::pair<SourceLocation, 
+                                         PartialDiagnostic> Note) {
   unsigned diag = PD.getDiagID();
 
   // FIXME: Add this assertion to help us flush out problems with
@@ -1864,6 +1866,10 @@ bool Sema::RequireCompleteType(SourceLocation Loc, QualType T,
   // We have an incomplete type. Produce a diagnostic.
   Diag(Loc, PD) << T;
 
+  // If we have a note, produce it.
+  if (!Note.first.isInvalid())
+    Diag(Note.first, Note.second);
+    
   // If the type was a forward declaration of a class/struct/union
   // type, produce
   const TagType *Tag = 0;