[GROOVY-9970] Type argument inference does not work in closure

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 4.0.0-alpha-3
• Component/s: Static compilation, Static Type Checker
• Assignee: Eric Milles
• Reporter: Stefanos Chaliasos
• Created: 08/Mar/21 08:31
• Updated: 02/May/21 09:18
• Resolved: 15/Mar/21 13:35

Description

I have the following Groovy program.

class Foo {}

final class A<T extends Foo> {
  public T x;
  A(T x) {
    this.x = x;
  }
}

@groovy.transform.CompileStatic
public class C<T extends Number> {
  public void foo(T args) {
    final A<Foo> x = new A<>(new Foo()); // compiles
    def closure = p -> {
        final A<Foo> y = new A<>(new Foo()); // does not compile
    }
  }
}

Actual Behavior

The program does not compile, and I get the following error.

org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
Foo.groovy: 15: [Static type checking] - Cannot call A#<init>(T) with arguments [Foo]
 @ line 15, column 26.
           final A<Foo> y = new A<>(new Foo()); 
                            ^

1 error

Expected Behavior

Compile successfully.

Comment

This should be a regression bug because it compiles with the 3.0.7 compiler and the 4.0.0-alpha-2.

Affected Version

This programs fails when compiled with the compiler from the master (commit: 5d2944523f198d96b6515e85a24d2b4e43ce665f).