Revert "[Sema] Fix crash on invalid code with parenthesized aggregate initialization" (#76272)

Reverts llvm/llvm-project#76232 and
7ab16fb520 to recover build bots.

Breaks libc++ tests, details in #76232

#76228

clang/lib/Sema/SemaInit.cpp

@@ -5512,14 +5512,6 @@ static void TryOrBuildParenListInitialization(
   } else if (auto *RT = Entity.getType()->getAs<RecordType>()) {
     bool IsUnion = RT->isUnionType();
     const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
-    if (RD->isInvalidDecl()) {
-      // Exit early to avoid confusion when processing members.
-      // We do the same for braced list initialization in
-      // `CheckStructUnionTypes`.
-      Sequence.SetFailed(
-          clang::InitializationSequence::FK_ParenthesizedListInitFailed);
-      return;
-    }
 
     if (!IsUnion) {
       for (const CXXBaseSpecifier &Base : RD->bases()) {

clang/test/SemaCXX/crash-GH76228.cpp

@@ -1,28 +0,0 @@
-// RUN: %clang_cc1 -std=c++20 -verify %s
-// Check we don't crash on incomplete members and bases when handling parenthesized initialization.
-class incomplete; // expected-note@-0 3  {{forward declaration of 'incomplete'}}
-struct foo {
-  int a;
-  incomplete b;
-  // expected-error@-1 {{incomplete type}}
-};
-foo a1(0);
-
-struct one_int {
-    int a;
-};
-struct bar : one_int, incomplete {};
-// expected-error@-1 {{incomplete type}}
-bar a2(0);
-
-incomplete a3[3](1,2,3);
-// expected-error@-1 {{incomplete type}}
-
-struct qux : foo {
-};
-qux a4(0);
-
-struct fred {
-    foo a[3];
-};
-fred a5(0);

clang/test/SemaCXX/paren-list-agg-init.cpp

@@ -289,7 +289,7 @@ int test() {
   // used to crash
   S a(0, 1);
   S b(0);
-  S c(0, 0, 1);
+  S c(0, 0, 1); // beforecxx20-warning {{aggregate initialization of type 'S' from a parenthesized list of values is a C++20 extension}}
 
   S d {0, 1};
   S e {0};