[jira] [Commented] (GROOVY-7753) regression of return type from ternary operator

["M. Justin (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/GROOVY-7753?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15856225#comment-15856225 ] 

M. Justin commented on GROOVY-7753:
-----------------------------------

I have the same issue when I attempt to assign the value to a variable, as well as when I use the empty list literal instead of Collections.emptyList.  Is this the same issue, or should I open a new issue for it?

{code}List<String> stringList1 = ['a'] ?: []
List<String> stringList2 = true ? ['b'] : []{code}

This is one place where Java has @CompileStatic Groovy beat, as its type inference does a better job with this sort of thing.

> regression of return type from ternary operator
> -----------------------------------------------
>
>                 Key: GROOVY-7753
>                 URL: https://issues.apache.org/jira/browse/GROOVY-7753
>             Project: Groovy
>          Issue Type: Bug
>          Components: Static compilation, Static Type Checker
>    Affects Versions: 2.4.6
>            Reporter: Jason Winnebeck
>
> In Groovy 2.4.5 the following code works, but in Groovy 2.4.6, it fails to compile:
> {code}
> @groovy.transform.Field
> String x = "X"
> @groovy.transform.CompileStatic
> public List<String> getStrings() {
> 	x ? [x] : Collections.emptyList()
> }
> getStrings()
> {code}
> In Groovy 2.4.6 the compile error is:
> {code}
> [Static type checking] - Incompatible generic argument types. Cannot assign java.util.List <? extends java.lang.Object> to: java.util.List <String>
>  @ line 6, column 2.
>     x ? [x] : Collections.emptyList()
>     ^
> {code}
> Workaround is to cast the result of emptyList to the erased type, (List) in this case.



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