[GROOVY-10774] Static compilation error using generic classes with maps

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.0.11, 3.0.12
• Fix Version/s: 3.0.13
• Component/s: Compiler
• Environment: Windows using Java 1.8.0_211
• Assignee: Eric Milles
• Reporter: AN
• Created: 29/Sep/22 18:33
• Updated: 10/Feb/23 21:40
• Resolved: 30/Sep/22 14:50

Description

I was updating an old library to use Groovy 3 and I found a static compilation error.  The error starts occurring since Groovy 2.5.16, previously tested versions of 2.5.x compile successfully.

The error can be reproduced with:

import groovy.transform.CompileStatic

@CompileStatic
class MyGenericClass<K> {
    //protected LinkedHashMap<K, String> valuesMap = new LinkedHashMap<>()
    protected Map<String, K> keysMap = new LinkedHashMap<>()

    void put(K k, String v) {
        keysMap.put(v, k)
        //valuesMap.put(k, v)
    }
} 

The error only happens when the parametrized type is used as the value of the map.

 

2022-09-29T14:24:28.708-0400 [ERROR] [system.err] C:\WP\GroovyGenerics\src\main\groovy\test\MyGenericClass.groovy: 11: [Static type checking] - Cannot call java.util.Map <String, K>#put(java.lang.String, K) with arguments [java.lang.String, K] 
2022-09-29T14:24:28.708-0400 [ERROR] [system.err]  @ line 11, column 9.
2022-09-29T14:24:28.708-0400 [ERROR] [system.err]            keysMap.put(v, k)
2022-09-29T14:24:28.708-0400 [ERROR] [system.err]            ^
2022-09-29T14:24:28.708-0400 [ERROR] [system.err] 
2022-09-29T14:24:28.708-0400 [ERROR] [system.err] 1 error
2022-09-29T14:24:28.708-0400 [ERROR] [system.err]