================
@@ -2940,18 +2940,28 @@ bool QualType::isBitwiseCloneableType(const ASTContext
&Context) const {
if (RD->mayInsertExtraPadding())
return false;
+ auto isCycleBackToRD = [RD](QualType T) {
+ return !T.isNull() && !T->containsErrors() &&
+ T.getCanonicalType()->getAsRecordDecl() == RD;
----------------
Xinlong-Chen wrote:
Thanks for the insightful review! You're right — I was overthinking it.
Checking for incomplete or invalid types is indeed sufficient.
Case 1: Forward-declared type — caught by isIncompleteType().
```
struct Bar;
struct Foo {
Bar bar;
};
static_assert(__is_bitwise_cloneable(Bar)
```
Case 2: Infinite recursion. After error recovery, the RecordDecl is marked
invalid, so we bail out early via RD->isInvalidDecl().
```
struct ABC {
ABCD ptr;
};
static_assert(__is_bitwise_cloneable(ABC) == true);
```
So the fix is simply adding:
```
if (RD->isInvalidDecl())
return false;
```
output:
```
/tmp/test_cycle2.cpp:2:3: error: unknown type name 'ABCD'; did you mean 'ABC'?
2 | ABCD ptr;
| ^~~~
| ABC
/tmp/test_cycle2.cpp:1:8: note: 'ABC' declared here
1 | struct ABC {
| ^
/tmp/test_cycle2.cpp:2:8: error: field has incomplete type 'ABC'
2 | ABCD ptr;
| ^
/tmp/test_cycle2.cpp:1:8: note: definition of 'ABC' is not complete until the
closing '}'
1 | struct ABC {
| ^
/tmp/test_cycle2.cpp:5:15: error: static assertion failed due to requirement
'__is_bitwise_cloneable(ABC) == true'
5 | static_assert(__is_bitwise_cloneable(ABC) == true);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
3 errors generated.
```
https://github.com/llvm/llvm-project/pull/183707
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