Scala compiler conflicts Java field names with class / package canonical names

[fdaca]

Test example

Foo.java

public class Foo {
    private String java;

    public java.lang.Integer test() {
        return null;
    }
}

Bar.scala

class Bar {
  def main(): Unit = {
    val bug = new Foo()
    bug.test()
  }
}

compilation result:

[error] /Users/fdaca/git/scala-bug-test/src/main/java/Foo.java:4:17: value lang is not a member of String
[error]     public java.lang.Integer test() {
[error]                 ^

Bug description

Given a mixed Java / Scala project with a Java class having both:

• a method declaration with a canonical name of return type (e.g. public java.lang.Integer test())
• a field with name equal to the first package of declared method return type (e.g. private String java)

Scala compiler would conflict the field identifier with package name and yield an error trying to lookup a member as if the first package was the previously declared field: value lang is not a member of String.

The same problem occurs with different identifiers: private Foo org; + public org.apache.commons.lang.CharSet getSet() would try to lookup member apache in type Foo.

Affected versions

• 2.13.1
• 2.12.8
• 2.11.8

[Jasper-M]

A workaround (other than adding imports in your Java files): if your Java files don't depend on your Scala files you can set compileOrder := CompileOrder.JavaThenScala in sbt.

[som-snytt]

Could have been a duplicate of Similar to #10350 but that fix did not do enough work.

[SethTisue]

@som-snytt you're saying this one is also fixed and we should close it?

[som-snytt]

I amended my comment and made the PR available for review. Open question is whether it's worth fixing on dotty, since this ticket has only 3 👍 from the field in 5 years.