8009459: Wrong behavior of diamond finder with source level 7

Summary: Diamond finder doesn't take into account different inference behaviors
Reviewed-by: jjg

src/share/classes/com/sun/tools/javac/comp/Attr.java

@@ -2151,8 +2151,11 @@ public class Attr extends JCTree.Visitor {
                     ResultInfo findDiamondResult = new ResultInfo(VAL,
                             resultInfo.checkContext.inferenceContext().free(resultInfo.pt) ? Type.noType : pt());
                     Type inferred = deferredAttr.attribSpeculative(tree, env, findDiamondResult).type;
+                    Type polyPt = allowPoly ?
+                            syms.objectType :
+                            clazztype;
                     if (!inferred.isErroneous() &&
-                        types.isAssignable(inferred, pt().hasTag(NONE) ? syms.objectType : pt(), types.noWarnings)) {
+                        types.isAssignable(inferred, pt().hasTag(NONE) ? polyPt : pt(), types.noWarnings)) {
                         String key = types.isSameType(clazztype, inferred) ?
                             "diamond.redundant.args" :
                             "diamond.redundant.args.1";

test/tools/javac/generics/diamond/T6939780.java → test/tools/javac/generics/diamond/6939780/T6939780.java

 /*
  * @test /nodynamiccopyright/
- * @bug 6939780 7020044
+ * @bug 6939780 7020044 8009459
  *
  * @summary  add a warning to detect diamond sites
  * @author mcimadamore
- * @compile/ref=T6939780.out T6939780.java -XDrawDiagnostics -XDfindDiamond
+ * @compile/ref=T6939780_7.out -Xlint:-options -source 7 T6939780.java -XDrawDiagnostics -XDfindDiamond
+ * @compile/ref=T6939780_8.out T6939780.java -XDrawDiagnostics -XDfindDiamond
  *
  */
 
 class T6939780 {
 
-    void test() {
-        class Foo<X extends Number> {
-            Foo() {}
-            Foo(X x) {}
-        }
+    static class Foo<X extends Number> {
+        Foo() {}
+        Foo(X x) {}
+    }
+
+    void testAssign() {
         Foo<Number> f1 = new Foo<Number>(1);
         Foo<?> f2 = new Foo<Number>();
         Foo<?> f3 = new Foo<Integer>();
@@ -22,4 +24,16 @@ class T6939780 {
         Foo<?> f5 = new Foo<Number>() {};
         Foo<?> f6 = new Foo<Integer>() {};
     }
+
+    void testMethod() {
+        gn(new Foo<Number>(1));
+        gw(new Foo<Number>());
+        gw(new Foo<Integer>());
+        gn(new Foo<Number>(1) {});
+        gw(new Foo<Number>() {});
+        gw(new Foo<Integer>() {});
+    }
+
+    void gw(Foo<?> fw) { }
+    void gn(Foo<Number> fn) { }
 }

test/tools/javac/generics/diamond/6939780/T6939780_7.out

+T6939780.java:21:28: compiler.warn.diamond.redundant.args: T6939780.Foo<java.lang.Number>, T6939780.Foo<java.lang.Number>
+T6939780.java:22:28: compiler.warn.diamond.redundant.args.1: T6939780.Foo<java.lang.Integer>, T6939780.Foo<java.lang.Number>
+T6939780.java:30:19: compiler.warn.diamond.redundant.args: T6939780.Foo<java.lang.Number>, T6939780.Foo<java.lang.Number>
+3 warnings

test/tools/javac/generics/diamond/6939780/T6939780_8.out

+T6939780.java:20:33: compiler.warn.diamond.redundant.args: T6939780.Foo<java.lang.Number>, T6939780.Foo<java.lang.Number>
+T6939780.java:21:28: compiler.warn.diamond.redundant.args: T6939780.Foo<java.lang.Number>, T6939780.Foo<java.lang.Number>
+T6939780.java:22:28: compiler.warn.diamond.redundant.args.1: T6939780.Foo<java.lang.Integer>, T6939780.Foo<java.lang.Number>
+T6939780.java:29:19: compiler.warn.diamond.redundant.args: T6939780.Foo<java.lang.Number>, T6939780.Foo<java.lang.Number>
+T6939780.java:30:19: compiler.warn.diamond.redundant.args: T6939780.Foo<java.lang.Number>, T6939780.Foo<java.lang.Number>
+T6939780.java:31:19: compiler.warn.diamond.redundant.args.1: T6939780.Foo<java.lang.Integer>, T6939780.Foo<java.lang.Number>
+6 warnings

test/tools/javac/generics/diamond/T6939780.out

-T6939780.java:18:33: compiler.warn.diamond.redundant.args: Foo<java.lang.Number>, Foo<java.lang.Number>
-T6939780.java:19:28: compiler.warn.diamond.redundant.args: Foo<java.lang.Number>, Foo<java.lang.Number>
-T6939780.java:20:28: compiler.warn.diamond.redundant.args.1: Foo<java.lang.Integer>, Foo<java.lang.Number>
-3 warnings