r374202 - [ObjC generics] Fix not inheriting type bounds in categories/extensions.
Volodymyr Sapsai via cfe-commits
cfe-commits at lists.llvm.org
Mon Oct 21 18:39:26 PDT 2019
That error looks strange and confusing to me too. My guess is that my change exposed some bug with literals. I’ve tried
NSDictionary* videoSettingsDictionary2 = [NSDictionary
dictionaryWithObject:@(best_fourcc)
forKey:(id)kCVPixelBufferPixelFormatTypeKey];
and
@interface GenericTest <KeyType> : NSObject
- (void)test:(const KeyType <NSCopying> _Nonnull)key;
@end
void anotherTest(GenericTest *t) {
[t test:(id)kCVPixelBufferPixelFormatTypeKey];
}
But they didn’t trigger the error. I need more time to investigate the issue but in the meantime you can fix the build by casting to the corresponding constant type, something like
(NSString *)kCVPixelBufferPixelFormatTypeKey : @(best_fourcc)
Thanks,
Volodymyr
> On Oct 21, 2019, at 14:37, Hans Wennborg <hans at chromium.org> wrote:
>
> Hi Volodymyr,
>
> This broke the Chrome build in an interesting way. Here's a reduced repro:
>
>
> $ cat /tmp/a.mm
> #import <AVFoundation/AVFoundation.h>
>
> void f(int width, int height) {
> FourCharCode best_fourcc = kCMPixelFormat_422YpCbCr8_yuvs;
> NSDictionary* videoSettingsDictionary = @{
> (id)kCVPixelBufferPixelFormatTypeKey : @(best_fourcc),
> };
> }
>
> $ build.release/bin/clang++ -isysroot
> /work/chromium/src/build/mac_files/xcode_binaries/Contents/Developer/Platforms/MacOSX.platform/Developer/SDK
> s/MacOSX10.14.sdk -c /tmp/a.mm
>
> /tmp/a.mm:6:5: error: cannot initialize a parameter of type
> 'KeyType<NSCopying> _Nonnull const' (aka 'const id') with an rvalue
> of type 'id'
> (id)kCVPixelBufferPixelFormatTypeKey : @(best_fourcc),
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 1 error generated.
>
>
> To me, the "cannot initialize a parameter of type [nanana] (aka 'const
> id') with an rvalue of type 'id'" message looks strange, but I'm not
> an Obj-C expert. Is this expected behaviour, and if so how should we
> change our code?
>
> Thanks,
> Hans
>
> On Wed, Oct 9, 2019 at 12:26 PM Volodymyr Sapsai via cfe-commits
> <cfe-commits at lists.llvm.org> wrote:
>>
>> Author: vsapsai
>> Date: Wed Oct 9 12:29:13 2019
>> New Revision: 374202
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=374202&view=rev
>> Log:
>> [ObjC generics] Fix not inheriting type bounds in categories/extensions.
>>
>> When a category/extension doesn't repeat a type bound, corresponding
>> type parameter is substituted with `id` when used as a type argument. As
>> a result, in the added test case it was causing errors like
>>
>>> type argument 'T' (aka 'id') does not satisfy the bound ('id<NSCopying>') of type parameter 'T'
>>
>> We are already checking that type parameters should be consistent
>> everywhere (see `checkTypeParamListConsistency`) and update
>> `ObjCTypeParamDecl` to have correct underlying type. And when we use the
>> type parameter as a method return type or a method parameter type, it is
>> substituted to the bounded type. But when we use the type parameter as a
>> type argument, we check `ObjCTypeParamType` that ignores the updated
>> underlying type and remains `id`.
>>
>> Fix by desugaring `ObjCTypeParamType` to the underlying type, the same
>> way we are doing with `TypedefType`.
>>
>> rdar://problem/54329242
>>
>> Reviewers: erik.pilkington, ahatanak
>>
>> Reviewed By: erik.pilkington
>>
>> Subscribers: jkorous, dexonsmith, ributzka, cfe-commits
>>
>> Differential Revision: https://reviews.llvm.org/D66696
>>
>> Modified:
>> cfe/trunk/include/clang/AST/Type.h
>> cfe/trunk/lib/AST/Type.cpp
>> cfe/trunk/test/SemaObjC/parameterized_classes_subst.m
>>
>> Modified: cfe/trunk/include/clang/AST/Type.h
>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/Type.h?rev=374202&r1=374201&r2=374202&view=diff
>> ==============================================================================
>> --- cfe/trunk/include/clang/AST/Type.h (original)
>> +++ cfe/trunk/include/clang/AST/Type.h Wed Oct 9 12:29:13 2019
>> @@ -5569,7 +5569,7 @@ class ObjCTypeParamType : public Type,
>>
>> public:
>> bool isSugared() const { return true; }
>> - QualType desugar() const { return getCanonicalTypeInternal(); }
>> + QualType desugar() const;
>>
>> static bool classof(const Type *T) {
>> return T->getTypeClass() == ObjCTypeParam;
>>
>> Modified: cfe/trunk/lib/AST/Type.cpp
>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/Type.cpp?rev=374202&r1=374201&r2=374202&view=diff
>> ==============================================================================
>> --- cfe/trunk/lib/AST/Type.cpp (original)
>> +++ cfe/trunk/lib/AST/Type.cpp Wed Oct 9 12:29:13 2019
>> @@ -663,6 +663,10 @@ ObjCTypeParamType::ObjCTypeParamType(con
>> initialize(protocols);
>> }
>>
>> +QualType ObjCTypeParamType::desugar() const {
>> + return getDecl()->getUnderlyingType();
>> +}
>> +
>> ObjCObjectType::ObjCObjectType(QualType Canonical, QualType Base,
>> ArrayRef<QualType> typeArgs,
>> ArrayRef<ObjCProtocolDecl *> protocols,
>>
>> Modified: cfe/trunk/test/SemaObjC/parameterized_classes_subst.m
>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaObjC/parameterized_classes_subst.m?rev=374202&r1=374201&r2=374202&view=diff
>> ==============================================================================
>> --- cfe/trunk/test/SemaObjC/parameterized_classes_subst.m (original)
>> +++ cfe/trunk/test/SemaObjC/parameterized_classes_subst.m Wed Oct 9 12:29:13 2019
>> @@ -467,3 +467,17 @@ void bar(MyMutableDictionary<NSString *,
>> - (void)mapUsingBlock2:(id)block { // expected-warning{{conflicting parameter types in implementation}}
>> }
>> @end
>> +
>> +// --------------------------------------------------------------------------
>> +// Use a type parameter as a type argument.
>> +// --------------------------------------------------------------------------
>> +// Type bounds in a category/extension are omitted. rdar://problem/54329242
>> + at interface ParameterizedContainer<T : id<NSCopying>>
>> +- (ParameterizedContainer<T> *)inInterface;
>> + at end
>> + at interface ParameterizedContainer<T> (Cat)
>> +- (ParameterizedContainer<T> *)inCategory;
>> + at end
>> + at interface ParameterizedContainer<U> ()
>> +- (ParameterizedContainer<U> *)inExtension;
>> + at end
>>
>>
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