Regression: scala fails to extend a Java class

[rcano]

Compiler version

3.1.+ all the way to 3.1.3RC

Minimized code

class MyTabbedPaneUI extends javax.swing.plaf.metal.MetalTabbedPaneUI {}

Output

bridge generated for member object TabbedPaneLayoutMetalTabbedPaneUI.this.TabbedPaneLayout in class MetalTabbedPaneUI
which overrides object TabbedPaneLayoutBasicTabbedPaneUI.this.TabbedPaneLayout in class BasicTabbedPaneUI
clashes with definition of the member itself; both have erased type MetalTabbedPaneUI.this.TabbedPaneLayout."

Expectation

It should compile.

[sjrd]

This already fails in 3.0.0 and 3.0.2. It's a regression wrt. Scala 2.x. 2.13.8 successfully compiles this snippet.

The TabbedPaneLayout it complains about is an inner class of two superclasses: MetalTabbedPaneUI#TabbedPaneLayout, but also BasicTabbedPaneUI#TabbedPaneLayout. Hence the clash. But no bridge should be generated for those things in the first place, since they're Java inner classes, not terms.

[rcano]

This already fails in 3.0.0 and 3.0.2. It's a regression wrt. Scala 2.x. 2.13.8 successfully compiles this snippet.

The TabbedPaneLayout it complains about is an inner class of two superclasses: MetalTabbedPaneUI#TabbedPaneLayout, but also BasicTabbedPaneUI#TabbedPaneLayout. Hence the clash. But no bridge should be generated for those things in the first place, since they're Java inner classes, not terms.

Interesting, it did compile on 3.0.0-RC1, I had a project at that version and found the issue when updating.