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

With updates the libc++ tests.

This reverts commit 2205d23 and relands
86dc6e1 and
7ab16fb.

Original commit was reverted because of failing libc++ tests, see llvm#76232 for
the discussion.

The errors in the tests are spurious in the first place (coming from initialization
of invalid classes), so update the tests to match new behavior that does
not show those errors.

Author: mordante

clang/lib/Sema/SemaInit.cpp

@@ -5512,6 +5512,14 @@ 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

@@ -0,0 +1,28 @@
+// 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); // beforecxx20-warning {{aggregate initialization of type 'S' from a parenthesized list of values is a C++20 extension}}
+  S c(0, 0, 1);
 
   S d {0, 1};
   S e {0};

libcxx/test/libcxx/utilities/expected/expected.expected/transform_error.mandates.verify.cpp

@@ -46,39 +46,31 @@ void test() {
   {
     std::expected<int, int> e;
     e.transform_error(return_unexpected<int&>); // expected-error-re@*:* {{static assertion failed {{.*}}The result of {{.*}} must be a valid template argument for unexpected}}
-    // expected-error-re@*:* {{{{(excess elements in struct initializer|no matching constructor for initialization of)}}{{.*}}}}
     // expected-error-re@*:* {{static assertion failed {{.*}}[expected.object.general] A program that instantiates the definition of template expected<T, E> for {{.*}} is ill-formed.}}
 
     e.transform_error(return_no_object<int&>); // expected-error-re@*:* {{static assertion failed {{.*}}The result of {{.*}} must be a valid template argument for unexpected}}
-    // expected-error-re@*:* {{{{(excess elements in struct initializer|no matching constructor for initialization of)}}{{.*}}}}
     // expected-error-re@*:* {{static assertion failed {{.*}}[expected.object.general] A program that instantiates the definition of template expected<T, E> for {{.*}} is ill-formed.}}
   }
 
   // Test const& overload
   {
     const std::expected<int, int> e;
     e.transform_error(return_unexpected<const int &>); // expected-error-re@*:* {{static assertion failed {{.*}}The result of {{.*}} must be a valid template argument for unexpected}}
-    // expected-error-re@*:* 2 {{{{(excess elements in struct initializer|no matching constructor for initialization of)}}{{.*}}}}
     e.transform_error(return_no_object<const int &>); // expected-error-re@*:* {{static assertion failed {{.*}}The result of {{.*}} must be a valid template argument for unexpected}}
-    // expected-error-re@*:* 2 {{{{(excess elements in struct initializer|no matching constructor for initialization of)}}{{.*}}}}
   }
 
   // Test && overload
   {
     std::expected<int, int> e;
     std::move(e).transform_error(return_unexpected<int&&>); // expected-error-re@*:* {{static assertion failed {{.*}}The result of {{.*}} must be a valid template argument for unexpected}}
-    // expected-error-re@*:* 2 {{{{(excess elements in struct initializer|no matching constructor for initialization of)}}{{.*}}}}
     std::move(e).transform_error(return_no_object<int&&>); // expected-error-re@*:* {{static assertion failed {{.*}}The result of {{.*}} must be a valid template argument for unexpected}}
-    // expected-error-re@*:* 2 {{{{(excess elements in struct initializer|no matching constructor for initialization of)}}{{.*}}}}
   }
 
   // Test const&& overload
   {
     const std::expected<int, int> e;
     std::move(e).transform_error(return_unexpected<const int&&>); // expected-error-re@*:* {{static assertion failed {{.*}}The result of {{.*}} must be a valid template argument for unexpected}}
-    // expected-error-re@*:* 2 {{{{(excess elements in struct initializer|no matching constructor for initialization of)}}{{.*}}}}
     std::move(e).transform_error(return_no_object<const int&&>); // expected-error-re@*:* {{static assertion failed {{.*}}The result of {{.*}} must be a valid template argument for unexpected}}
-    // expected-error-re@*:* 2 {{{{(excess elements in struct initializer|no matching constructor for initialization of)}}{{.*}}}}
   }
 }
 // clang-format on

libcxx/test/libcxx/utilities/expected/expected.void/transform_error.mandates.verify.cpp

@@ -46,39 +46,31 @@ void test() {
   {
     std::expected<void, int> e;
     e.transform_error(return_unexpected<int&>); // expected-error-re@*:* {{static assertion failed {{.*}}The result of {{.*}} must be a valid template argument for unexpected}}
-    // expected-error-re@*:* {{{{(excess elements in struct initializer|no matching constructor for initialization of)}}{{.*}}}}
     // expected-error-re@*:* {{static assertion failed {{.*}}A program that instantiates expected<T, E> with a E that is not a valid argument for unexpected<E> is ill-formed}}
 
     e.transform_error(return_no_object<int&>); // expected-error-re@*:* {{static assertion failed {{.*}}The result of {{.*}} must be a valid template argument for unexpected}}
-    // expected-error-re@*:* {{{{(excess elements in struct initializer|no matching constructor for initialization of)}}{{.*}}}}
     // expected-error-re@*:* {{static assertion failed {{.*}}A program that instantiates expected<T, E> with a E that is not a valid argument for unexpected<E> is ill-formed}}
   }
 
   // Test const& overload
   {
     const std::expected<void, int> e;
     e.transform_error(return_unexpected<const int &>); // expected-error-re@*:* {{static assertion failed {{.*}}The result of {{.*}} must be a valid template argument for unexpected}}
-    // expected-error-re@*:* {{{{(excess elements in struct initializer|no matching constructor for initialization of)}}{{.*}}}}
     e.transform_error(return_no_object<const int &>); // expected-error-re@*:* {{static assertion failed {{.*}}The result of {{.*}} must be a valid template argument for unexpected}}
-    // expected-error-re@*:* {{{{(excess elements in struct initializer|no matching constructor for initialization of)}}{{.*}}}}
   }
 
   // Test && overload
   {
     std::expected<void, int> e;
     std::move(e).transform_error(return_unexpected<int&&>); // expected-error-re@*:* {{static assertion failed {{.*}}The result of {{.*}} must be a valid template argument for unexpected}}
-    // expected-error-re@*:* {{{{(excess elements in struct initializer|no matching constructor for initialization of)}}{{.*}}}}
     std::move(e).transform_error(return_no_object<int&&>); // expected-error-re@*:* {{static assertion failed {{.*}}The result of {{.*}} must be a valid template argument for unexpected}}
-    // expected-error-re@*:* {{{{(excess elements in struct initializer|no matching constructor for initialization of)}}{{.*}}}}
   }
 
   // Test const&& overload
   {
     const std::expected<void, int> e;
     std::move(e).transform_error(return_unexpected<const int&&>); // expected-error-re@*:* {{static assertion failed {{.*}}The result of {{.*}} must be a valid template argument for unexpected}}
-    // expected-error-re@*:* {{{{(excess elements in struct initializer|no matching constructor for initialization of)}}{{.*}}}}
     std::move(e).transform_error(return_no_object<const int&&>); // expected-error-re@*:* {{static assertion failed {{.*}}The result of {{.*}} must be a valid template argument for unexpected}}
-    // expected-error-re@*:* {{{{(excess elements in struct initializer|no matching constructor for initialization of)}}{{.*}}}}
   }
 }
 // clang-format on