If the user is trying to apply the -> or . member reference operator

to a function or function pointer, it's probably because the user
forgot to put in parentheses () to call the function.

llvm-svn: 67826

clang/include/clang/Basic/DiagnosticSemaKinds.td

@@ -872,6 +872,9 @@ def err_typecheck_member_reference_type : Error<
   "cannot refer to type member %0 with '%select{.|->}1'">;
 def err_typecheck_member_reference_unknown : Error<
   "cannot refer to member %0 with '%select{.|->}1'">;
+def note_member_reference_needs_call : Note<
+  "perhaps you meant to call this function with '()'?">;
+
 def err_typecheck_incomplete_tag : Error<"incomplete definition of type %0">;
 def err_typecheck_no_member : Error<"no member named %0">;
 def err_member_redeclared : Error<"class member cannot be redeclared">;

clang/lib/Sema/SemaExpr.cpp

@@ -2101,9 +2101,22 @@ Sema::ActOnMemberReferenceExpr(Scope *S, ExprArg Base, SourceLocation OpLoc,
                                                     MemberLoc));
   }
 
-  return ExprError(Diag(MemberLoc,
+  Diag(MemberLoc, diag::err_typecheck_member_reference_struct_union)
-                        diag::err_typecheck_member_reference_struct_union)
+    << BaseType << BaseExpr->getSourceRange();
-                     << BaseType << BaseExpr->getSourceRange());
+
+  // If the user is trying to apply -> or . to a function or function
+  // pointer, it's probably because they forgot parentheses to call
+  // the function. Suggest the addition of those parentheses.
+  if (BaseType == Context.OverloadTy || 
+      BaseType->isFunctionType() ||
+      (BaseType->isPointerType() && 
+       BaseType->getAsPointerType()->isFunctionType())) {
+    SourceLocation Loc = PP.getLocForEndOfToken(BaseExpr->getLocEnd());
+    Diag(Loc, diag::note_member_reference_needs_call)
+      << CodeModificationHint::CreateInsertion(Loc, "()");
+  }
+
+  return ExprError();
 }
 
 /// ConvertArgumentsForCall - Converts the arguments specified in

clang/test/SemaCXX/member-expr.cpp

@@ -20,3 +20,14 @@ void test(X* xp, X x) {
   float f1 = x.g();
   float f2 = xp->g();
 }
+
+struct A {
+ int f0;
+};
+struct B {
+ A *f0();
+};
+int f0(B *b) {
+  return b->f0->f0; // expected-error{{member reference base type 'struct A *(void)' is not a structure or union}} \
+  // expected-note{{perhaps you meant to call this function}}
+}