[AST][RecoveryAST] Preseve more invalid return stmt.

suppress the diagnostics for missing return stmt in constexpr func.

Differential Revision: https://reviews.llvm.org/D82284

clang/lib/Sema/SemaStmt.cpp

@@ -3629,7 +3629,8 @@ Sema::ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp,
                       Scope *CurScope) {
   // Correct typos, in case the containing function returns 'auto' and
   // RetValExp should determine the deduced type.
-  ExprResult RetVal = CorrectDelayedTyposInExpr(RetValExp);
+  ExprResult RetVal = CorrectDelayedTyposInExpr(
+      RetValExp, nullptr, /*RecoverUncorrectedTypos=*/true);
   if (RetVal.isInvalid())
     return StmtError();
   StmtResult R = BuildReturnStmt(ReturnLoc, RetVal.get());

clang/test/SemaCXX/constant-expression-cxx11.cpp

@@ -1807,11 +1807,10 @@ namespace PR15884 {
 }
 
 namespace AfterError {
-  // FIXME: Suppress the 'no return statements' diagnostic if the body is invalid.
-  constexpr int error() { // expected-error {{no return statement}}
+  constexpr int error() {
     return foobar; // expected-error {{undeclared identifier}}
   }
-  constexpr int k = error();
+  constexpr int k = error(); // expected-error {{constexpr variable 'k' must be initialized by a constant expression}}
 }
 
 namespace std {

clang/test/SemaCXX/typo-correction-crash.cpp

@@ -16,7 +16,8 @@ template <class A> struct is_same<A,A> { static constexpr bool value = true; };
 
 auto L1 = [] { return s; }; // expected-error {{use of undeclared identifier 's'}}
 using T1 = decltype(L1());
-static_assert(is_same<T1, void>::value, "Return statement should be discarded");
+// FIXME: Suppress the 'undeclared identifier T1' diagnostic, the UsingDecl T1 is discarded because of an invalid L1().
+static_assert(is_same<T1, void>::value, "Return statement should be discarded"); // expected-error {{use of undeclared identifier 'T1'}}
 auto L2 = [] { return tes; }; // expected-error {{use of undeclared identifier 'tes'; did you mean 'test'?}}
 using T2 = decltype(L2());
 static_assert(is_same<T2, int>::value, "Return statement was corrected");