[jira] [Closed] (GROOVY-10480) Closure that assigns null to object changes the type of variable

["Thodoris Sotiropoulos (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/GROOVY-10480?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Thodoris Sotiropoulos closed GROOVY-10480.
------------------------------------------
    Resolution: Duplicate

Duplicate of https://issues.apache.org/jira/browse/GROOVY-10356.

> Closure that assigns null to object changes the type of variable
> ----------------------------------------------------------------
>
>                 Key: GROOVY-10480
>                 URL: https://issues.apache.org/jira/browse/GROOVY-10480
>             Project: Groovy
>          Issue Type: Bug
>          Components: Static Type Checker
>            Reporter: Thodoris Sotiropoulos
>            Priority: Major
>
> I have the following Groovy program
> {code:java}
> class Foo {
>   void foo() {}
> }
> class Main  {
>   static void bar() {
>     def x = new Foo();
>     if (false) {
>       x = null;
>     }
>     x.foo(); // works
>   }
>   static void baz() {
>     def x  = new Foo();
>     def clos = { -> {
>       x = null;
>       
>     }}
>     x.foo(); // fails
>   }
> }
> {code}
> h3. Actual behaviour
> The assignment that takes inside closure changes the type of variable `x`, even though closure is never being called.
> The compilerthen rejects the program by raising the following error message.
> {code}
> org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
> test.groovy: 22: [Static type checking] - A closure shared variable [x] has been assigned with various types and the method [foo()] does not exist in the lowest upper bound of those types: [java.lang.Object]. In general, this is a bad practice (variable reuse) because the compiler cannot determine safely what is the type of the variable at the moment of the call in a multithreaded context.
>  @ line 22, column 5.
>        x.foo();
>        ^
> 1 error
> {code}
> h3. Expected behaviour
> Compile successfully
> Tested against master (https://github.com/apache/groovy/commit/5601ea14304b67e71586b0196e38f90fa1a46f5b).



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