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  1. Groovy
  2. GROOVY-10544

Static compiler chooses superinterface return type

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      I am using Vavr 0.10, which has the following type relationship:

      Try<T> extends Value<T>

      Value defines the method <U> Value<U> map(Function<? super T, ? extends U> mapper), which is narrowed in the interface definition for Try to return a Try<U>. When used in a functional pipeline, however, the STC infers Value<U> as the return type even when it knows that the previous value is a Try<T>, causing downstream type failures. Instead, it should infer that the return type is the more specific Try<U>.

      I am inspecting this intermediate inference in Groovy-Eclipse, but the CLI errors I'm getting are exactly consistent with the erroneous inference. I will try to create a minimal replication after getting the ticket ID.


      This feels like the same problem:

      List<DeleteItemRequest> batch = createBatch() // from Amazon DynamoDB SDK 2
      Map<String, List<DeleteItemRequest>> requestsByTable = 
        batch.stream().collect(toMap(DeleteItemRequest::tableName, List::of))
      

      This results in the error

      Groovy:Failed to find the expected method[tableName(java.lang.Object)] in the type[software.amazon.awssdk.services.dynamodb.model.DeleteItemRequest]
      

      even though from the context it's clear that the type being submitted is DeleteItemRequest, and Groovy-Eclipse correctly identifies Stream<DeleteItemRequest>. Somehow the "inner generics context" of toMap isn't getting the information, which also accounts for the functional-pipeline glitch.

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          Eric Milles
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          Eric Milles

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              emilles Eric Milles
              chrylis Christopher Smith
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