Help: Get Generic Pattern Detail From TypeDecl in AST

dduan · 2016-01-11T22:31:17.000Z

Hi all,

Working on a swiftc crash in the type checker, I’m having a hard time with getting generic type pattern in the AST. For example, say we have parsed:

struct Y<T> {}
struct X<T, U> {
let a: Y<T>
let b: Y<U>
}

In the AST, the type of member “a” would be “Y<T>". But I can’t figure out how to inspect the inner “T” from the TypeDecl instance that represents a’s type.

What am I missing here?

- Daniel

jtbandes · 2016-01-11T22:34:54.000Z

You might find BoundGenericType useful:

github.com

apple/swift/blob/5aa40dd0aa057591398339c77df91a976ae35c72/include/swift/AST/Types.h#L1438


      
          };
          BEGIN_CAN_TYPE_WRAPPER(UnboundGenericType, Type)
            PROXY_CAN_TYPE_SIMPLE_GETTER(getParent)
          END_CAN_TYPE_WRAPPER(UnboundGenericType, Type)
          
          inline CanType getAsCanType(const Type &type) { return CanType(type); }
          typedef ArrayRefView<Type,CanType,getAsCanType> CanTypeArrayRef;
          
          /// BoundGenericType - An abstract class for applying a generic
          /// nominal type to the given type arguments.
          class BoundGenericType : public TypeBase, public llvm::FoldingSetNode {
            NominalTypeDecl *TheDecl;
          
            /// \brief The type of the parent, in which this type is nested.
            Type Parent;
            
            ArrayRef<Type> GenericArgs;
            
          
          protected:
            BoundGenericType(TypeKind theKind, NominalTypeDecl *theDecl, Type parent,

Jacob Bandes-Storch

···

On Mon, Jan 11, 2016 at 2:31 PM, Daniel Duan via swift-dev < swift-dev@swift.org> wrote:

Hi all,

Working on a swiftc crash in the type checker, I’m having a hard time with
getting generic type pattern in the AST. For example, say we have parsed:

struct Y<T> {}
struct X<T, U> {
let a: Y<T>
let b: Y<U>
}

In the AST, the type of member “a” would be “Y<T>". But I can’t figure
out how to inspect the inner “T” from the TypeDecl instance that represents
a’s type.

What am I missing here?

- Daniel
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swift-dev mailing list
swift-dev@swift.org
https://lists.swift.org/mailman/listinfo/swift-dev

dduan · 2016-01-11T23:32:05.000Z

BoundGenericType::getGenericArgs() is exactly what I was looking for. Thanks Jacob!

···

On Jan 11, 2016, at 2:34 PM, Jacob Bandes-Storch <jtbandes@gmail.com> wrote:

You might find BoundGenericType useful:

https://github.com/apple/swift/blob/5aa40dd0aa057591398339c77df91a976ae35c72/include/swift/AST/Types.h#L1438

Jacob Bandes-Storch

On Mon, Jan 11, 2016 at 2:31 PM, Daniel Duan via swift-dev <swift-dev@swift.org <mailto:swift-dev@swift.org>> wrote:
Hi all,

Working on a swiftc crash in the type checker, I’m having a hard time with getting generic type pattern in the AST. For example, say we have parsed:

struct Y<T> {}
struct X<T, U> {
let a: Y<T>
let b: Y<U>
}

In the AST, the type of member “a” would be “Y<T>". But I can’t figure out how to inspect the inner “T” from the TypeDecl instance that represents a’s type.

What am I missing here?

- Daniel
_______________________________________________
swift-dev mailing list
swift-dev@swift.org <mailto:swift-dev@swift.org>
https://lists.swift.org/mailman/listinfo/swift-dev