Breakpoint doesn't work on lambdas which returns a generic type

[gayanper]

Take the following code blocks

package com.example.demo;

import java.util.Optional;
import java.util.function.Function;

public class Test {
  public static void main(String[] args) {
    map(t -> Optional.ofNullable(t), "Null").isPresent();
  }

  private static <T, R> Optional<? extends R> map(Function<? super T, ? extends Optional<? extends R>> mapper, T value) {
    return mapper.apply(value);
  }
}

package com.example.demo;

import java.util.Optional;
import java.util.function.Function;

public class Test {
  public static void main(String[] args) {
    map(t -> Optional.ofNullable(t), "Null").isPresent();
  }

  private static <T, R> Optional<R> map(Function<T, Optional<R>> mapper, T value) {
    return mapper.apply(value);
  }
}

package com.example.demo;

import java.util.Optional;
import java.util.function.Function;

public class Test {
  public static void main(String[] args) {
    map(t -> Optional.ofNullable(t), "Null").isPresent();
  }

  private static Optional<String> map(Function<String, Optional<String>> mapper, String value) {
    return mapper.apply(value);
  }
}

Environment

• Operating System: Any
• JDK version: 17
• Visual Studio Code version: 1.79.2
• Java extension version: 1.20
• Java Debugger extension version: 0.52

Steps To Reproduce

1. Add inline breakpoint into t -> Optional.ofNullable(t)
2. Run the program

Current Result

The breakpoint doesn't work

Expected Result

The execution should stop at the lambda

Additional Informations

The issue is when trying to find lambda methods from the debugger API, the method object doesn't provide the generic signature, But the signature we try to match has the generic signature which cause the match failure.

[gayanper]

If I change the map method to

  private static Optional<String> map(Function<String, Optional> mapper, String value) {
    return mapper.apply(value);
  }

everything works

[gayanper]

Move to microsoft/java-debug#498