[GROOVY-10330] STC instantiates type variable with a wrong type when calling an instance method of the same class

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 4.0.0-beta-2, 3.0.11, 2.5.19
• Component/s: Static Type Checker
• Assignee: Eric Milles
• Reporter: Thodoris Sotiropoulos
• Created: 26/Oct/21 14:13
• Updated: 13/Sep/22 19:08
• Resolved: 30/Oct/21 16:00

Description

I have the following program

import java.util.function.Function;

class A<T> {
  T y;
  void foo(T x, Function<T, T> func) {
    foo((true) ? x : y, func)
  }
}

Actual behavior

org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
test.groovy: 6: [Static type checking] - Cannot call A#foo(java.lang.Object, java.util.function.Function<java.lang.Object, java.lang.Object>) with arguments [java.lang.Object<T>, java.util.function.Function<T, T>]
 @ line 6, column 5.
       foo((true) ? x : y, func)
       ^

1 error

Expected behaviour

Compile successfully

Note: If replace `Function<T, T> func` with `Supplier<T> func`, the code compiles as expected.

Tested against master.