[GROOVY-10363] STC produces compile-time error on encoutering bounded type parameter with conditional

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.0.11, 4.0.3
• Component/s: Static Type Checker
• Assignee: Eric Milles
• Reporter: Thodoris Sotiropoulos
• Created: 12/Nov/21 09:32
• Updated: 24/Jul/22 12:16
• Resolved: 16/May/22 15:00

Description

I have the following program:

import java.util.function.Supplier;

class A {
  static final <X extends Supplier<Number>> X m(X x, X y) {
    X z = (true) ? x : y
    z
  }
}

Actual behavior

org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
test.groovy: 10: [Static type checking] - Incompatible generic argument types. Cannot assign java.util.function.Supplier<java.lang.Object> to: X
 @ line 10, column 5.
       z
       ^

1 error

Compile successfully

NOTE: The bug is triggered only when the type parameter is named other than `T`.

Tested against master

Issue Links

• relates to: GROOVY-10601 Incompatible generic argument type when combining conditionals and bounded type parameters