fix lambda to anonymous class regression (#336)

* fix lambda to anonymous class option

* add regression tests for feature

* get method references to decompile correctly again

src/org/jetbrains/java/decompiler/main/ClassWriter.java

@@ -192,10 +192,10 @@ public void classLambdaToJava(ClassNode node, TextBuffer buffer, Exprent method_
         MethodDescriptor md_lambda = MethodDescriptor.parseDescriptor(node.lambdaInformation.method_descriptor);
 
         boolean simpleLambda = false;
+        boolean written = false;
 
         if (!lambdaToAnonymous) {
           RootStatement root = wrapper.getMethodWrapper(mt.getName(), mt.getDescriptor()).root;
-          boolean written = false;
           if (DecompilerContext.getOption(IFernflowerPreferences.MARK_CORRESPONDING_SYNTHETICS)) {
             buffer.append("/* ")
               .appendMethod(node.lambdaInformation.content_method_name,
@@ -310,16 +310,16 @@ public void classLambdaToJava(ClassNode node, TextBuffer buffer, Exprent method_
                 }
               }
             }
-
-            if (!simpleLambda) {
-              buffer.append(" {").appendLineSeparator();
-
-              methodLambdaToJava(node, wrapper, mt, buffer, indent + 1, !lambdaToAnonymous);
-
-              buffer.appendIndent(indent).append("}");
-            }
           }
         }
+
+        if ((!simpleLambda && !written) || lambdaToAnonymous) {
+          buffer.append(" {").appendLineSeparator();
+
+          methodLambdaToJava(node, wrapper, mt, buffer, indent + 1, !lambdaToAnonymous);
+
+          buffer.appendIndent(indent).append("}");
+        }
       }
     }
     finally {

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

@@ -140,6 +140,17 @@ public String getMethodDoc(StructClass structClass, StructMethod structMethod) {
       IFernflowerPreferences.VERIFY_ANONYMOUS_CLASSES, "1",
       IFernflowerPreferences.MARK_CORRESPONDING_SYNTHETICS, "1"
       );
+    registerSet("Lambda to Anonymous Class", this::registerLambdaToAnonymousClass,
+      IFernflowerPreferences.BYTECODE_SOURCE_MAPPING, "1",
+      IFernflowerPreferences.DUMP_ORIGINAL_LINES, "1",
+      IFernflowerPreferences.DUMP_EXCEPTION_ON_ERROR, "0",
+      IFernflowerPreferences.IGNORE_INVALID_BYTECODE, "1",
+      IFernflowerPreferences.VERIFY_ANONYMOUS_CLASSES, "1",
+      IFernflowerPreferences.INCLUDE_ENTIRE_CLASSPATH, "0",
+      IFernflowerPreferences.TERNARY_CONDITIONS, "1",
+      IFernflowerPreferences.FORCE_JSR_INLINE, "1",
+      IFernflowerPreferences.LAMBDA_TO_ANONYMOUS_CLASS, "1"
+    );
     // TODO: user renamer class test
   }
 
@@ -843,4 +854,9 @@ private void registerSyntheticsMarking() {
     register(JAVA_8, "TestAnonymousClassNaming");
     register(JAVA_8, "TestLocalClassNaming");
   }
+
+  private void registerLambdaToAnonymousClass() {
+    register(JAVA_8, "TestLambdaToAnonymousClass");
+    register(JAVA_8, "TestLambdaToAnonymousClass2");
+  }
 }

testData/results/pkg/TestLambdaToAnonymousClass.dec

@@ -0,0 +1,24 @@
+package pkg;
+
+public class TestLambdaToAnonymousClass {
+   Runnable f = new Runnable() {
+      public run() {
+         System.out.println();// 4
+      }
+   };
+}
+
+class 'pkg/TestLambdaToAnonymousClass' {
+   method 'lambda$new$0 ()V' {
+      0      5
+      1      5
+      2      5
+      3      5
+      4      5
+      5      5
+      6      6
+   }
+}
+
+Lines mapping:
+4 <-> 6

testData/results/pkg/TestLambdaToAnonymousClass2.dec

@@ -0,0 +1,83 @@
+package pkg;
+
+import java.util.List;
+import java.util.function.BiConsumer;
+import java.util.function.Function;
+import java.util.function.IntFunction;
+
+public class TestLambdaToAnonymousClass2 {
+   public void test() {
+      BiConsumer<List<String>, Integer> $ = new BiConsumer() {// 8
+         public accept(List l, Integer i) {
+            Character[] a = (Character[])l.stream().map(new Function() {// 9
+               public apply(String st) {
+                  return st.charAt(i);// 10
+               }
+            }).toArray(new IntFunction() {
+               public apply(int x$0) {
+                  return new Character[x$0];// 11
+               }
+            });
+         }// 12
+      };
+   }// 13
+}
+
+class 'pkg/TestLambdaToAnonymousClass2' {
+   method 'test ()V' {
+      5      9
+      6      22
+   }
+
+   method 'lambda$test$2 (Ljava/util/List;Ljava/lang/Integer;)V' {
+      0      11
+      1      11
+      2      11
+      3      11
+      4      11
+      5      11
+      c      11
+      d      11
+      e      11
+      f      11
+      10      11
+      16      15
+      17      15
+      18      15
+      19      15
+      1a      15
+      1b      11
+      1c      11
+      1d      11
+      1e      11
+      1f      20
+   }
+
+   method 'lambda$null$0 (Ljava/lang/Integer;Ljava/lang/String;)Ljava/lang/Character;' {
+      0      13
+      1      13
+      2      13
+      3      13
+      4      13
+      5      13
+      6      13
+      7      13
+      8      13
+      9      13
+      a      13
+      b      13
+   }
+
+   method 'lambda$null$1 (I)[Ljava/lang/Character;' {
+      0      17
+      4      17
+   }
+}
+
+Lines mapping:
+8 <-> 10
+9 <-> 12
+10 <-> 14
+11 <-> 18
+12 <-> 21
+13 <-> 23

testData/src/java8/pkg/TestLambdaToAnonymousClass.java

@@ -0,0 +1,5 @@
+package pkg;
+
+public class TestLambdaToAnonymousClass {
+  Runnable f = () -> System.out.println();
+}

testData/src/java8/pkg/TestLambdaToAnonymousClass2.java

@@ -0,0 +1,14 @@
+package pkg;
+
+import java.util.List;
+import java.util.function.*;
+
+public class TestLambdaToAnonymousClass2 {
+  public void test() {
+    BiConsumer<List<String>, Integer> $ = (l, i) -> {
+      Character[] a = l.stream()
+        .map(st -> st.charAt(i))
+        .toArray(Character[]::new);
+    };
+  }
+}