Fixed method references to constructors causing VerifyError on Android

Android doesn't like a non-empty stack when we return from a method Fixes #67
luontola · Sep 6, 2015 · b8c21e4 · b8c21e4
1 parent ac4a374
commit b8c21e4
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diff --git a/README.md b/README.md
@@ -208,6 +208,11 @@ optimizations to that mechanism may break Retrolambda.
 Version History
 ---------------
 
+### Upcoming
+
+- Fixed method references to constructors causing VerifyError on Android 
+  ([Issue #67](https://github.com/orfjackal/retrolambda/issues/67))
+
 ### Retrolambda 2.0.5 (2015-07-19)
 
 - Support for lambdas with marker interfaces

diff --git a/retrolambda/src/main/java/net/orfjackal/retrolambda/lambdas/BackportLambdaClass.java b/retrolambda/src/main/java/net/orfjackal/retrolambda/lambdas/BackportLambdaClass.java
@@ -154,17 +154,15 @@ public void visitMethodInsn(int opcode, String owner, String name, String desc,
                         && accessMethod.getTag() == H_INVOKESTATIC) {
                     // The impl is a private constructor which is called through an access method.
                     // XXX: The current method already did NEW an instance, but we won't use it because
-                    // the access method will also instantiate it, so we could remove the unused
-                    // instance from stack using the following code, but this is not strictly necessary
-                    // because ARETURN is allowed to leave behind a non-empty stack. We could improve
-                    // this backporter so that it would remove the unnecessary "NEW, DUP" instructions,
-                    // but that would be complicated.
-                    if (false) {
-                        super.visitVarInsn(ASTORE, 1);
-                        super.visitInsn(POP);
-                        super.visitInsn(POP);
-                        super.visitVarInsn(ALOAD, 1);
-                    }
+                    // the access method will also instantiate it.
+                    // - The JVM would be OK with a non-empty stack on ARETURN, but it causes a VerifyError
+                    //   on Android, so here we remove the unused instance from the stack.
+                    // - We could improve this backporter so that it would remove the unnecessary
+                    //   "NEW, DUP" instructions, but that would be complicated.
+                    super.visitVarInsn(ASTORE, 1);
+                    super.visitInsn(POP);
+                    super.visitInsn(POP);
+                    super.visitVarInsn(ALOAD, 1);
                 }
             } else {
                 super.visitMethodInsn(opcode, owner, name, desc, itf);