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Luke Daley commented on GROOVY-7582: ------------------------------------ FWIW, I've hit this in Ratpack. The Groovy API is based around closure coercion for the most part, so my basic strategy is to design for Java 8 which means that it works nice with Groovy. Unfortunately, I didn't know about this issue when I added some API. > Closure to SAM coercion doesn't handle overloads with different SAM signatures > ------------------------------------------------------------------------------ > > Key: GROOVY-7582 > URL: https://issues.apache.org/jira/browse/GROOVY-7582 > Project: Groovy > Issue Type: Bug > Affects Versions: 2.4.4 > Reporter: Luke Daley > > The following… > {code} > interface Action<T> { > void exec(T thing) > } > interface Block { > void exec() > } > class Container { > void m(Action<?> action) {} > void m(Block block) {} > } > def c = new Container() > c.m { -> 1 } > {code} > Yields… > {code} > groovy.lang.GroovyRuntimeException: Ambiguous method overloading for method > Container#m. > Cannot resolve which method to invoke for [class > ConsoleScript0$_run_closure1] due to overlapping prototypes between: > [interface Action] > [interface Block] > at ConsoleScript0.run(ConsoleScript0:16) > {code} > It seems that Groovy should be able to deal with the case where the SAM > parameter signatures are different. Java does this with lambda expressions. > That is, the following works in Java… > {code} > Container c = new Container(); > c.m(() -> {}); > c.m(arg -> {}); > {code} -- This message was sent by Atlassian JIRA (v6.3.4#6332)