[jira] [Commented] (GROOVY-10651) STC: closure parameter type inference for raw type that is iterable over type parameter

["Eric Milles (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/GROOVY-10651?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17550666#comment-17550666 ] 

Eric Milles commented on GROOVY-10651:
--------------------------------------

One part of this problem is that the generics for "Iterable<TN>" and "Iterator<TN>" are different for binary and source types.  When ResolveVisitor processes the source, it sets the type "TreeNode<?>" as the redirect for the TN type (see [ResolveVisitor#resolveGenericsType|https://github.com/apache/groovy/blob/4fc7c5d290725b7120ee3466d81da2ce94e770d3/src/main/java/org/codehaus/groovy/control/ResolveVisitor.java#L1493]).  However, both the ASM and ClassLoader resolution (via ClassNodeResolver) leaves "TN -> Object" for the generics type.

Since the sample uses a raw type "void proc(TreeNode node)", there is no type argument for "TN" and so the ClassNode of the GenericsType is used instead.  This is where "Cannot find matching method #proc(java.lang.Object)" comes from.

> STC: closure parameter type inference for raw type that is iterable over type parameter
> ---------------------------------------------------------------------------------------
>
>                 Key: GROOVY-10651
>                 URL: https://issues.apache.org/jira/browse/GROOVY-10651
>             Project: Groovy
>          Issue Type: Bug
>          Components: Static Type Checker
>    Affects Versions: 2.5.17, 3.0.11, 4.0.3
>            Reporter: Eric Milles
>            Assignee: Eric Milles
>            Priority: Major
>
> Consider the following:
> {code:java}
> abstract class TreeNode<TN extends TreeNode<?>> implements Iterable<TN> {
>   @Override
>   Iterator<TN> iterator() {
>   }
> }
> {code}
> {code:groovy}
> void proc(TreeNode node) {
>   node.eachWithIndex { child, index ->
>     proc(child) // Cannot find matching method #proc(java.lang.Object)
>   }
> }
> {code}



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