Add a test for the missing lambda body (#328)

test/org/jetbrains/java/decompiler/SingleClassesTest.java

@@ -694,6 +694,9 @@ private void registerDefault() {
     register(JAVA_21_PREVIEW, "TestRawProcessor");
     register(JAVA_21_PREVIEW, "TestFmtProcessor");
     register(JAVA_21_PREVIEW, "TestCustomProcessor");
+
+    // TODO: lambda body is erased
+    register(JASM, "TestMissingLambdaBody");
   }
 
   private void registerEntireClassPath() {

testData/results/pkg/TestMissingLambdaBody.dec

@@ -0,0 +1,108 @@
+package pkg;
+
+import java.util.function.Consumer;
+
+public class TestMissingLambdaBody {
+   public void init() {
+      this.visit(var1 -> {// 24 31
+      });// 69
+   }// 32
+
+   public void visit(Consumer var1) {
+      var1.accept("Foo".hashCode());// 38 39 40 41 42
+      var1.accept("Bar".length());// 43 44 45 46 47
+   }// 48
+
+   public Number accept(Number var1) {
+      System.out.println(var1);// 54 55 56
+      return var1;// 57 58
+   }
+}
+
+class 'pkg/TestMissingLambdaBody' {
+   method 'init ()V' {
+      0      6
+      7      6
+      8      6
+      9      6
+      a      8
+   }
+
+   method 'lambda$init$0 (Ljava/lang/Integer;)V' {
+      9      7
+   }
+
+   method 'visit (Ljava/util/function/Consumer;)V' {
+      0      11
+      1      11
+      2      11
+      3      11
+      4      11
+      5      11
+      6      11
+      7      11
+      8      11
+      9      11
+      a      11
+      b      11
+      c      11
+      d      11
+      e      12
+      f      12
+      10      12
+      11      12
+      12      12
+      13      12
+      14      12
+      15      12
+      16      12
+      17      12
+      18      12
+      19      12
+      1a      12
+      1b      12
+      1c      13
+   }
+
+   method 'accept (Ljava/lang/Number;)Ljava/lang/Number;' {
+      0      16
+      1      16
+      2      16
+      3      16
+      4      16
+      5      16
+      6      16
+      7      17
+      8      17
+   }
+}
+
+Lines mapping:
+24 <-> 7
+31 <-> 7
+32 <-> 9
+38 <-> 12
+39 <-> 12
+40 <-> 12
+41 <-> 12
+42 <-> 12
+43 <-> 13
+44 <-> 13
+45 <-> 13
+46 <-> 13
+47 <-> 13
+48 <-> 14
+54 <-> 17
+55 <-> 17
+56 <-> 17
+57 <-> 18
+58 <-> 18
+69 <-> 8
+Not mapped:
+25
+26
+64
+65
+66
+67
+68

testData/src/jasm/TestMissingLambdaBody.jasm

@@ -0,0 +1,75 @@
+/**
+ * This code can be assembled with <a href="https://wiki.openjdk.java.net/display/CodeTools/asmtools">asmtools</a>
+ * using <code>asmtools jasm -g *.jasm</code> command line.
+ */
+package  pkg;
+
+super public class TestMissingLambdaBody
+  version 52:0
+{
+  // weird fix
+  const #1 = Method TestMissingLambdaBody.lambda$init$0:"(Ljava/lang/Integer;)V";
+
+  public Method "<init>":"()V"
+  stack 1 locals 1
+  {
+    aload_0;
+    invokespecial  Method java/lang/Object."<init>":"()V";
+    return;
+
+  }
+  public Method init:"()V"
+  stack 2 locals 1
+  {
+    aload_0;
+    aload_0;
+    invokedynamic  InvokeDynamic REF_invokeStatic:Method java/lang/invoke/LambdaMetafactory.metafactory:"(Ljava/lang/invoke/MethodHandles$Lookup;Ljava/lang/String;Ljava/lang/invoke/MethodType;Ljava/lang/invoke/MethodType;Ljava/lang/invoke/MethodHandle;Ljava/lang/invoke/MethodType;)Ljava/lang/invoke/CallSite;":accept:"(Lpkg/TestMissingLambdaBody;)Ljava/util/function/Consumer;" {
+      MethodType "(Ljava/lang/Object;)V",
+      MethodHandle REF_invokeVirtual:#1,
+      MethodType "(Ljava/lang/Integer;)V"
+    };
+    invokevirtual  Method visit:"(Ljava/util/function/Consumer;)V";
+    return;
+
+  }
+  public Method visit:"(Ljava/util/function/Consumer;)V"
+  stack 2 locals 2
+  {
+    aload_1;
+    ldc  String "Foo";
+    invokevirtual  Method java/lang/String.hashCode:"()I";
+    invokestatic  Method java/lang/Integer.valueOf:"(I)Ljava/lang/Integer;";
+    invokeinterface  InterfaceMethod java/util/function/Consumer.accept:"(Ljava/lang/Object;)V",  2;
+    aload_1;
+    ldc  String "Bar";
+    invokevirtual  Method java/lang/String.length:"()I";
+    invokestatic  Method java/lang/Integer.valueOf:"(I)Ljava/lang/Integer;";
+    invokeinterface  InterfaceMethod java/util/function/Consumer.accept:"(Ljava/lang/Object;)V",  2;
+    return;
+
+  }
+  public Method accept:"(Ljava/lang/Number;)Ljava/lang/Number;"
+  stack 2 locals 2
+  {
+    getstatic  Field java/lang/System.out:"Ljava/io/PrintStream;";
+    aload_1;
+    invokevirtual  Method java/io/PrintStream.println:"(Ljava/lang/Object;)V";
+    aload_1;
+    areturn;
+
+  }
+  private synthetic Method lambda$init$0:"(Ljava/lang/Integer;)V"
+  stack 2 locals 2
+  {
+    aload_0;
+    aload_1;
+    invokevirtual  Method accept:"(Ljava/lang/Number;)Ljava/lang/Number;";
+    checkcast java/lang/Integer; // No idea why javac would compile this checkcast
+    pop;
+    return;
+
+  }
+
+  public static final InnerClass Lookup=class java/lang/invoke/MethodHandles$Lookup of class java/lang/invoke/MethodHandles;
+
+} // end Class TestMissingLambdaBody