[Wdocumentation] fixes an assertion failure with typedefed function and block pointer

Summary:
The assertion happens when compiling with -Wdocumentation with variable declaration to a typedefed function pointer. I not too familiar with the ObjC syntax but first two tests assert without this patch.

Fixes https://bugs.llvm.org/show_bug.cgi?id=42844

Reviewers: gribozavr

Reviewed By: gribozavr

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D66706

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@370677 91177308-0d34-0410-b5e6-96231b3b80d8

lib/AST/CommentSema.cpp

@@ -588,6 +588,8 @@ void Sema::checkReturnsCommand(const BlockCommandComment *Command) {
   if (isObjCPropertyDecl())
     return;
   if (isFunctionDecl() || isFunctionOrBlockPointerVarLikeDecl()) {
+    assert(!ThisDeclInfo->ReturnType.isNull() &&
+           "should have a valid return type");
     if (ThisDeclInfo->ReturnType->isVoidType()) {
       unsigned DiagKind;
       switch (ThisDeclInfo->CommentDecl->getKind()) {
@@ -873,6 +875,12 @@ bool Sema::isFunctionOrBlockPointerVarLikeDecl() {
   // can be ignored.
   if (QT->getAs<TypedefType>())
     return false;
+  if (const auto *P = QT->getAs<PointerType>())
+    if (P->getPointeeType()->getAs<TypedefType>())
+      return false;
+  if (const auto *P = QT->getAs<BlockPointerType>())
+    if (P->getPointeeType()->getAs<TypedefType>())
+      return false;
   return QT->isFunctionPointerType() || QT->isBlockPointerType();
 }
 

test/Sema/warn-documentation.cpp

@@ -1360,3 +1360,34 @@ using VariadicFnType2 = void (*)(int a, ...);
  */
 class EmptyNoteNoCrash {
 };
+
+namespace PR42844 { // Assertion failures when using typedefed function pointers
+typedef void (*AA)();
+typedef AA A();
+A *a; ///< \return none
+// expected-warning@-1 {{'\return' command used in a comment that is not attached to a function or method declaration}}
+
+typedef void B();
+B *b; ///< \return none
+// expected-warning@-1 {{'\return' command used in a comment that is not attached to a function or method declaration}}
+
+void CC();
+typedef void C();
+C &c = CC; ///< \return none
+// expected-warning@-1 {{'\return' command used in a comment that is not attached to a function or method declaration}}
+
+using DD = void(*)();
+using D = DD();
+D *d; ///< \return none
+// expected-warning@-1 {{'\return' command used in a comment that is not attached to a function or method declaration}}
+
+using E = void();
+E *e; ///< \return none
+// expected-warning@-1 {{'\return' command used in a comment that is not attached to a function or method declaration}}
+
+void FF();
+using F = void();
+F &f = FF; ///< \return none
+// expected-warning@-1 {{'\return' command used in a comment that is not attached to a function or method declaration}}
+
+} // namespace PR42844

test/Sema/warn-documentation.m

@@ -310,3 +310,11 @@ void (^_Nullable blockPointerVariableThatLeadsNowhere)();
  * now should work too.
  */
 typedef void (^VariadicBlockType)(int a, ...);
+
+// PR42844 - Assertion failures when using typedefed block pointers
+typedef void(^VoidBlockType)();
+typedef VoidBlockType VoidBlockTypeCall();
+VoidBlockTypeCall *d; ///< \return none
+// expected-warning@-1 {{'\return' command used in a comment that is not attached to a function or method declaration}}
+VoidBlockTypeCall ^e; ///< \return none
+// expected-warning@-1 {{'\return' command used in a comment that is not attached to a function or method declaration}}