[GROOVY-8084] Captured types doesn't work in @CompileStatic

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.4.8
• Fix Version/s: 3.0.0-alpha-4, 2.5.3
• Component/s: Static compilation, Static Type Checker
• Assignee: Daniel Sun
• Reporter: Alexey Afanasiev
• Created: 08/Feb/17 10:06
• Updated: 13/Dec/18 10:05
• Resolved: 24/Aug/18 19:57

Description

This code could be successfully compiled and executed.

@CompileStatic
static def method(List<? extends Serializable> captured) {
    captured.add('some string')
    return captured
}

println method(new ArrayList<Integer>())

Looks like type check in groovy doesn't work with captured types. Is it a bug?

Is there any documentation about generics in groovy?

P.S.:
Another kind of strange behaviour:

@CompileStatic
static def method() {
    List<Integer> list = new ArrayList<>()
    List<? extends Serializable> captured = list
    captured.add('some string') //Error:(7, 5) Groovyc: [Static type checking] - Cannot call java.util.ArrayList <java.lang.Integer>#add(java.lang.Integer) with arguments [java.lang.String]
    return captured
}

Somehow type checking infered type of 'captured' variable to java.util.ArrayList <java.lang.Integer>