Strange bytecode generated for anonymous lambda class

Issue #286 resolved
Jesper Öqvist
created an issue

ExtendJ 8.1.0-47-gdeb1b1c Java SE 8

ExtendJ generates weird bytecode for the anonymous class implementing the second lambda expression in this test:

import java.util.*;
import java.util.stream.*;
public class Test {
  public static void main(String[] args) {
    String[] names = { "Alice", "Bob", "Acorn" };
    IntStream ints = strLen(Arrays.asList(names));
    ints.forEach(i -> System.out.println(i));
  }

  static IntStream strLen(List<? extends String> names) {
    return names.stream().mapToInt(name -> name.length());
  }
}

The test compiles and runs fine, but the generated bytecode is strange. The relevant parts of the class Test$2 are:

  public int applyAsInt(wildcards.? extends String);
    flags: ACC_PUBLIC
    Code:
      stack=1, locals=2, args_size=2
         0: aload_1       
         1: invokevirtual #24                 // Method java/lang/String.length:()I
         4: ireturn       
      LineNumberTable:
        line 11: 0
      LocalVariableTable:
        Start  Length  Slot  Name   Signature
               0       5     0  this   LTest$2;
               0       5     1  name   Ljava/lang/String;
    Signature: #27                          // (Lwildcards/? extends String;)I

  public int applyAsInt(java.lang.Object);
    flags: ACC_PUBLIC, ACC_BRIDGE, ACC_SYNTHETIC
    Code:
      stack=2, locals=2, args_size=2
         0: aload_0       
         1: aload_1       
         2: checkcast     #20                 // class java/lang/String
         5: invokevirtual #32                 // Method applyAsInt:(Ljava/lang/String;)I
         8: ireturn       
      LineNumberTable:
        line 0: 0
      LocalVariableTable:
        Start  Length  Slot  Name   Signature
               0       9     0  this   LTest$2;
               0       9     1    p0   Ljava/lang/Object;

The method type signature for the first method is strange, and the second bridge method should not be needed if the first method argument is reified.

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