InstanceOfPatternMatch gives wrong type parameter

[nazoking]

What version of OpenRewrite are you using?

I am using

• OpenRewrite v6.16.2
• Maven/Gradle plugin v6.16.2
• org.openrewrite.recipe:rewrite-migrate-java:2.18.1

How are you running OpenRewrite?

I am using the Gradle plugin, and my project is a multi module project.

initscript {
    repositories {
        maven { url "https://plugins.gradle.org/m2" }
    }
    dependencies {
        classpath("org.openrewrite:plugin:6.16.2")
    }
}

rootProject {
    plugins.apply(org.openrewrite.gradle.RewritePlugin)
    dependencies {
        rewrite("org.openrewrite.recipe:rewrite-spring:latest.release")
        rewrite("org.openrewrite.recipe:rewrite-migrate-java:2.18.1")
    }

    afterEvaluate {
        if (repositories.isEmpty()) {
            repositories {
                mavenCentral()
            }
        }
    }
}

and run

./gradlew --init-script rewrite.gradle rewriteRun -Drewrite.activeRecipe=org.openrewrite.staticanalysis.InstanceOfPatternMatch

What is the smallest, simplest way to reproduce the problem?

A code snippet can be something simple like this.

        if(obj instanceof List) {
            test((List)list);
        }

     static public String test(List<String> list){

What did you expect to see?

        if(obj instanceof List list) {
            test(list);
        }

     static public String test(List<String> list){

What did you see instead?

        if(obj instanceof List<?> list) {
            test(list);
        }

     static public String test(List<String> list){

List<?> is not the same as List , this will result in a compilation error like this:

 error: incompatible types: List<CAP#1> cannot be converted to List<String>
            test(list));
            ^
  where CAP#1 is a fresh type-variable:
    CAP#1 extends Object from capture of ?

Are you interested in contributing a fix to OpenRewrite?

Indicate if this is something you would like to work on, and how we can best support you in doing so.

[timtebeek]

Thanks for the detailed report once again @nazoking ! Indeed an issue with how we handle generics. Would you be willing to turn the above into a runnable unit test and start a draft PR as a step up to a fix?