[GROOVY-5842] Runtimer error when types down match with Map and Map.Entry when using @CompileStatic

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.0.5
• Fix Version/s: 2.3.0-beta-1
• Component/s: Static compilation
• Labels: @CompileStatic exception runtime
• Environment: IDEA IC-123.23
• Assignee: Cédric Champeau
• Reporter: Oliver Plow
• Created: 07/Dec/12 03:57
• Updated: 05/Apr/14 00:00
• Resolved: 15/Jan/14 11:15

Description

When running the follow code a runtime error occurs:

@CompileStatic
class Scratch
{

    @CompileStatic
    public static void main(String[] args)
    {
        def Map<String, Set<String>> map = new HashMap<>()
        def set = new HashSet<String>()
        set.add("foo")
        map.put("bar", set)

        map.each {
            println(it.getKey()) // Groovyc: [Static type checking] - Cannot find matching method java.lang.Object#getKey().
            def List<String> list = it.getValue() // Groovyc: [Static type checking] - Cannot find matching method java.lang.Object#getKey().
        }

        // compiles fine and created runtime error
        // Cannot cast object '[foo]' with class 'java.util.HashSet' to class 'java.util.List' due to: groovy.lang.GroovyRuntimeException: Could not find matching constructor for: java.util.List(java.lang.String)
        map.each { Map.Entry<String, List<String>> entry ->
            println(entry.getKey())
            def List<String> list = entry.getValue()
        }
    }
}

Reason is that the type parameters for Map<String, Set<String>> and Map.Entry<String, List<String>> don't match, but the compiler doesn't reject it, although @CompileStatic is defined

Issue Links

• depends upon: GROOVY-5924 Provide a mechanism to allow the type checker to know what are the expected argument types of a closure