[clang] e27b5f9 - [clang][AST] Fix crash when printing error

[Ellis Hoag via cfe-commits]

Author: Ellis Hoag
Date: 2022-01-02T18:03:42-08:00
New Revision: e27b5f9371382952eb5482ad151bb6fcb4cd0d7c

URL: https://github.com/llvm/llvm-project/commit/e27b5f9371382952eb5482ad151bb6fcb4cd0d7c
DIFF: https://github.com/llvm/llvm-project/commit/e27b5f9371382952eb5482ad151bb6fcb4cd0d7c.diff

LOG: [clang][AST] Fix crash when printing error

Clang will crash if it tries to compile the following code. This commit
fixes it.
```
$ cat foo.c
void foo(_Nullable int *ptr) {
    __auto_type _Nonnull a = ptr;
};
$ clang foo.c -c -Wnullable-to-nonnull-conversion
```

Reviewed By: sammccall

Differential Revision: https://reviews.llvm.org/D116342

Added: 
    

Modified: 
    clang/lib/AST/TypePrinter.cpp
    clang/test/Sema/nullability.c

Removed: 
    


################################################################################
diff  --git a/clang/lib/AST/TypePrinter.cpp b/clang/lib/AST/TypePrinter.cpp
index 2a33a69f288d4..cf520fcb037ed 100644
--- a/clang/lib/AST/TypePrinter.cpp
+++ b/clang/lib/AST/TypePrinter.cpp
@@ -280,7 +280,7 @@ bool TypePrinter::canPrefixQualifiers(const Type *T,
     case Type::Attributed: {
       // We still want to print the address_space before the type if it is an
       // address_space attribute.
-      const auto *AttrTy = cast<AttributedType>(T);
+      const auto *AttrTy = cast<AttributedType>(UnderlyingType);
       CanPrefixQualifiers = AttrTy->getAttrKind() == attr::AddressSpace;
     }
   }

diff  --git a/clang/test/Sema/nullability.c b/clang/test/Sema/nullability.c
index d462886de0436..977b29e9bf9dd 100644
--- a/clang/test/Sema/nullability.c
+++ b/clang/test/Sema/nullability.c
@@ -125,6 +125,7 @@ void nullable_to_nonnull(_Nullable int *ptr) {
   int *a = ptr; // okay
   _Nonnull int *b = ptr; // expected-warning{{implicit conversion from nullable pointer 'int * _Nullable' to non-nullable pointer type 'int * _Nonnull'}}
   b = ptr; // expected-warning{{implicit conversion from nullable pointer 'int * _Nullable' to non-nullable pointer type 'int * _Nonnull'}}
+  __auto_type _Nonnull c = ptr; // expected-warning{{implicit conversion from nullable pointer 'int * _Nullable' to non-nullable pointer type 'int * _Nullable _Nonnull'}}
 
   accepts_nonnull_1(ptr); // expected-warning{{implicit conversion from nullable pointer 'int * _Nullable' to non-nullable pointer type 'int * _Nonnull'}}
 }