RFR JDK-8206142: type inference: javac is incorrectly applying capture conversion during incorporation

[B. Blaser]

Hi Vicente,

On 20 July 2018 at 22:27, Vicente Romero <vicente.romero at oracle.com> wrote:
> Hi all,
>
> Please review the patch to fix [1] at [2]. The fix is putting javac in sync
> with the spec by not applying capture conversion during incorporation.
>
> Thanks,
> Vicente
>
> [1] https://bugs.openjdk.java.net/browse/JDK-8206142
> [2] http://cr.openjdk.java.net/~vromero/8206142/webrev.00/jdk.dev.patch

It's hard to measure the potential side-effects of this fix, but it
seems good to me even if you'll probably need another review.
Maybe, I'd rewrite it as next to avoid creating a new method?

Thanks,
Bernard


diff -r b0fcf59be391
src/jdk.compiler/share/classes/com/sun/tools/javac/code/Types.java
--- a/src/jdk.compiler/share/classes/com/sun/tools/javac/code/Types.java
       Fri Jul 20 14:48:41 2018 -0700
+++ b/src/jdk.compiler/share/classes/com/sun/tools/javac/code/Types.java
       Sat Jul 21 14:33:05 2018 +0200
@@ -1003,24 +1003,24 @@
      * Is t an unchecked subtype of s?
      */
     public boolean isSubtypeUnchecked(Type t, Type s, Warner warn) {
-        boolean result = isSubtypeUncheckedInternal(t, s, true, warn);
+        boolean result = isSubtypeUnchecked(t, s, true, warn);
         if (result) {
             checkUnsafeVarargsConversion(t, s, warn);
         }
         return result;
     }
     //where
-        private boolean isSubtypeUncheckedInternal(Type t, Type s,
boolean capture, Warner warn) {
+        public boolean isSubtypeUnchecked(Type t, Type s, boolean
capture, Warner warn) {
             if (t.hasTag(ARRAY) && s.hasTag(ARRAY)) {
                 if (((ArrayType)t).elemtype.isPrimitive()) {
                     return isSameType(elemtype(t), elemtype(s));
                 } else {
-                    return isSubtypeUncheckedInternal(elemtype(t),
elemtype(s), false, warn);
+                    return isSubtypeUnchecked(elemtype(t),
elemtype(s), false, warn);
                 }
             } else if (isSubtype(t, s, capture)) {
                 return true;
             } else if (t.hasTag(TYPEVAR)) {
-                return isSubtypeUncheckedInternal(t.getUpperBound(),
s, false, warn);
+                return isSubtypeUnchecked(t.getUpperBound(), s, false, warn);
             } else if (!s.isRaw()) {
                 Type t2 = asSuper(t, s.tsym);
                 if (t2 != null && t2.isRaw()) {
diff -r b0fcf59be391
src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Infer.java
--- a/src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Infer.java
       Fri Jul 20 14:48:41 2018 -0700
+++ b/src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Infer.java
       Sat Jul 21 14:33:05 2018 +0200
@@ -1180,7 +1180,7 @@
         IS_SUBTYPE() {
             @Override
             boolean apply(Type op1, Type op2, Warner warn, Types types) {
-                return types.isSubtypeUnchecked(op1, op2, warn);
+                return types.isSubtypeUnchecked(op1, op2, false, warn);
             }
         },
         IS_SAME_TYPE() {