Commit Graph

12 Commits

Author SHA1 Message Date
Volodymyr Sapsai 65f58878e7 [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 wasn't updated and
remains `id`.

Fix by updating not only `ObjCTypeParamDecl` UnderlyingType but also
TypeForDecl as we use the underlying type to create a canonical type for
`ObjCTypeParamType` (see `ASTContext::getObjCTypeParamType`).

This is a different approach to fixing the issue. The previous one was
02c2ab3d88 which was reverted in
4c539e8da1. The problem with the previous
approach was that `ObjCTypeParamType::desugar` was returning underlying
type for `ObjCTypeParamDecl` without applying any protocols stored in
`ObjCTypeParamType`. It caused inconsistencies in comparing types before
and after desugaring.

Re-applying after fixing intermittent test failures.

rdar://problem/54329242

Reviewed By: erik.pilkington

Differential Revision: https://reviews.llvm.org/D72872
2020-04-24 16:32:28 -07:00
Volodymyr Sapsai 8fb7cfcea9 Revert "[ObjC generics] Fix not inheriting type bounds in categories/extensions."
This reverts commit a8c8b627f2. It causes
intermittent

    Clang :: SemaObjC/parameterized_classes_subst.m

test failures on various bots.
2020-04-07 17:41:30 -07:00
Volodymyr Sapsai a8c8b627f2 [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 wasn't updated and
remains `id`.

Fix by updating not only `ObjCTypeParamDecl` UnderlyingType but also
TypeForDecl as we use the underlying type to create a canonical type for
`ObjCTypeParamType` (see `ASTContext::getObjCTypeParamType`).

This is a different approach to fixing the issue. The previous one was
02c2ab3d88 which was reverted in
4c539e8da1. The problem with the previous
approach was that `ObjCTypeParamType::desugar` was returning underlying
type for `ObjCTypeParamDecl` without applying any protocols stored in
`ObjCTypeParamType`. It caused inconsistencies in comparing types before
and after desugaring.

rdar://problem/54329242

Reviewed By: erik.pilkington

Differential Revision: https://reviews.llvm.org/D72872
2020-04-03 16:29:02 -07:00
Hans Wennborg 4c539e8da1 Revert r374202"[ObjC generics] Fix not inheriting type bounds in categories/extensions."
This introduced new errors, see below. Reverting until that can be investigated
properly.

  #import <AVFoundation/AVFoundation.h>

  void f(int width, int height) {
    FourCharCode best_fourcc = kCMPixelFormat_422YpCbCr8_yuvs;
    NSDictionary* videoSettingsDictionary = @{
      (id)kCVPixelBufferPixelFormatTypeKey : @(best_fourcc),
    };
  }

  $ clang++ -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.

> 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
2019-10-22 22:39:01 +02:00
Volodymyr Sapsai 02c2ab3d88 [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

llvm-svn: 374202
2019-10-09 19:29:13 +00:00
Volodymyr Sapsai 4b512c36b6 [ObjC] Fix non-canonical types preventing type arguments substitution.
`QualType::substObjCTypeArgs` doesn't go past non-canonical types and as
the result misses some of the substitutions like `ObjCTypeParamType`.

Update `SimpleTransformVisitor` to traverse past the type sugar.

Reviewers: ahatanak, erik.pilkington

Reviewed By: erik.pilkington

Subscribers: jkorous, dexonsmith, cfe-commits

Differential Revision: https://reviews.llvm.org/D57270

llvm-svn: 354164
2019-02-15 20:17:45 +00:00
Manman Ren c5705bae05 ObjectiveC Generics: Start using ObjCTypeParamType.
For ObjC type parameter, we used to have TypedefType that is canonicalized to
id or the bound type. We can't represent "T <protocol>" and thus will lose
the type information in the following example:
@interface MyMutableDictionary<KeyType, ObjectType> : NSObject
- (void)setObject:(ObjectType)obj forKeyedSubscript:(KeyType <NSCopying>)key;
@end
MyMutableDictionary<NSString *, NSString *> *stringsByString;
NSNumber *n1, *n2;
stringsByString[n1] = n2;
--> no warning on type mismatch of the key.

To fix the problem, we introduce a new type ObjCTypeParamType that supports
a list of protocol qualifiers.

We create ObjCTypeParamType for ObjCTypeParamDecl when we create
ObjCTypeParamDecl. We also substitute ObjCTypeParamType instead of TypedefType
on an ObjCTypeParamDecl.

rdar://24619481
rdar://25060179

Differential Revision: http://reviews.llvm.org/D23080

llvm-svn: 281358
2016-09-13 17:41:05 +00:00
Douglas Gregor 1ac1b63c9c Implement variance for Objective-C type parameters.
Introduce co- and contra-variance for Objective-C type parameters,
which allows us to express that (for example) an NSArray is covariant
in its type parameter. This means that NSArray<NSMutableString *> * is
a subtype of NSArray<NSString *> *, which is expected of the immutable
Foundation collections.

Type parameters can be annotated with __covariant or __contravariant
to make them co- or contra-variant, respectively. This feature can be
detected by __has_feature(objc_generics_variance). Implements
rdar://problem/20217490.

llvm-svn: 241549
2015-07-07 03:58:54 +00:00
Douglas Gregor ab209d83be Implement the Objective-C __kindof type qualifier.
The __kindof type qualifier can be applied to Objective-C object
(pointer) types to indicate id-like behavior, which includes implicit
"downcasting" of __kindof types to subclasses and id-like message-send
behavior. __kindof types provide better type bounds for substitutions
into unspecified generic types, which preserves more type information.

llvm-svn: 241548
2015-07-07 03:58:42 +00:00
Douglas Gregor 10dc9d80cb Warn when an intended Objective-C specialization was actually a useless protocol qualification.
Warn in cases where one has provided redundant protocol qualification
that might be a typo for a specialization, e.g., NSArray<NSObject>,
which is pointless (NSArray declares that it conforms to NSObject) and
is likely to be a typo for NSArray<NSObject *>, i.e., an array of
NSObject pointers. This warning is very narrow, only applying when the
base type being qualified is parameterized, has the same number of
parameters as their are protocols listed, all of the names can also
refer to types (including Objective-C class types, of course), and at
least one of those types is an Objective-C class (making this a typo
for a missing '*'). The limitations are partly for performance reasons
(we don't want to do redundant name lookup unless we really need to),
and because we want the warning to apply in very limited cases to
limit false positives.

Part of rdar://problem/6294649.

llvm-svn: 241547
2015-07-07 03:58:28 +00:00
Douglas Gregor c5e07f5c11 Improve the Objective-C common-type computation used by the ternary operator.
The Objective-C common-type computation had a few problems that
required a significant rework, including:
  - Quadradic behavior when finding the common base type; now it's
  linear.
  - Keeping around type arguments when computing the common type
  between a specialized and an unspecialized type
  - Introducing redundant protocol qualifiers.

Part of rdar://problem/6294649. Also fixes rdar://problem/19572837 by
addressing a longstanding bug in
ASTContext::CollectInheritedProtocols().

llvm-svn: 241544
2015-07-07 03:58:01 +00:00
Douglas Gregor e83b95641f Substitute type arguments into uses of Objective-C interface members.
When messaging a method that was defined in an Objective-C class (or
category or extension thereof) that has type parameters, substitute
the type arguments for those type parameters. Similarly, substitute
into property accesses, instance variables, and other references.

This includes general infrastructure for substituting the type
arguments associated with an ObjCObject(Pointer)Type into a type
referenced within a particular context, handling all of the
substitutions required to deal with (e.g.) inheritance involving
parameterized classes. In cases where no type arguments are available
(e.g., because we're messaging via some unspecialized type, id, etc.),
we substitute in the type bounds for the type parameters instead.

Example:

  @interface NSSet<T : id<NSCopying>> : NSObject <NSCopying>
  - (T)firstObject;
  @end

  void f(NSSet<NSString *> *stringSet, NSSet *anySet) {
    [stringSet firstObject]; // produces NSString*
    [anySet firstObject]; // produces id<NSCopying> (the bound)
  }

When substituting for the type parameters given an unspecialized
context (i.e., no specific type arguments were given), substituting
the type bounds unconditionally produces type signatures that are too
strong compared to the pre-generics signatures. Instead, use the
following rule:

  - In covariant positions, such as method return types, replace type
    parameters with “id” or “Class” (the latter only when the type
    parameter bound is “Class” or qualified class, e.g,
    “Class<NSCopying>”)
  - In other positions (e.g., parameter types), replace type
    parameters with their type bounds.
  - When a specialized Objective-C object or object pointer type
    contains a type parameter in its type arguments (e.g.,
    NSArray<T>*, but not NSArray<NSString *> *), replace the entire
    object/object pointer type with its unspecialized version (e.g.,
    NSArray *).

llvm-svn: 241543
2015-07-07 03:57:53 +00:00