[GROOVY-8190] CompileStatic cant infer type when using map as map key

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.4.6
• Component/s: Static Type Checker
• Assignee: Eric Milles
• Reporter: Richard Zhang
• Created: 15/May/17 13:32
• Updated: 08/Mar/22 12:16
• Resolved: 11/Oct/21 17:45

Description

open groovy console, paste code below

import groovy.transform.*

@CompileStatic
void foo(Map<Map<String, String>, List<Map<String, Object>>> map){
    for(Map<String, String> key : map.keySet()) {
        def x = map[key]
        def y = x[0][""]
    }
}

and you will see it fails to compile

Result: org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
ideaGroovyConsole.groovy: 7: [Static type checking] - Cannot find matching method java.lang.Object#getAt(int). Please check if the declared type is right and if the method exists.
 @ line 7, column 17.
           def y = x[0][""]
                   ^
1 error
	at org.codehaus.groovy.control.ErrorCollector.failIfErrors(ErrorCollector.java:310)
	at org.codehaus.groovy.control.CompilationUnit.applyToPrimaryClassNodes(CompilationUnit.java:1075)
	at org.codehaus.groovy.control.CompilationUnit.doPhaseOperation(CompilationUnit.java:591)
	at org.codehaus.groovy.control.CompilationUnit.processPhaseOperations(CompilationUnit.java:569)
	at org.codehaus.groovy.control.CompilationUnit.compile(CompilationUnit.java:546)
	at groovy.lang.GroovyClassLoader.doParseClass(GroovyClassLoader.java:298)
	at groovy.lang.GroovyClassLoader.parseClass(GroovyClassLoader.java:268)
	at groovy.lang.GroovyShell.parseClass(GroovyShell.java:688)
	at groovy.lang.GroovyShell.run(GroovyShell.java:517)
	at groovy.lang.GroovyShell.run(GroovyShell.java:497)
	at sun.reflect.GeneratedMethodAccessor3.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.codehaus.groovy.runtime.callsite.PogoMetaMethodSite$PogoCachedMethodSite.invoke(PogoMetaMethodSite.java:169)
	at org.codehaus.groovy.runtime.callsite.PogoMetaMethodSite.call(PogoMetaMethodSite.java:71)
	at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:133)
	at console.run(console.txt:25)
	at groovy.ui.GroovyMain.processReader(GroovyMain.java:631)
	at groovy.ui.GroovyMain.processFiles(GroovyMain.java:539)
	at groovy.ui.GroovyMain.run(GroovyMain.java:382)
	at groovy.ui.GroovyMain.process(GroovyMain.java:370)
	at groovy.ui.GroovyMain.processArgs(GroovyMain.java:129)
	at groovy.ui.GroovyMain.main(GroovyMain.java:109)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.codehaus.groovy.tools.GroovyStarter.rootLoader(GroovyStarter.java:109)
	at org.codehaus.groovy.tools.GroovyStarter.main(GroovyStarter.java:131)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at com.intellij.rt.execution.CommandLineWrapper.main(CommandLineWrapper.java:65)

and if you change map key to other type (e.g a List<>), it will compile just fine.