6910550: javac 1.5.0_17 fails with incorrect error message

Summary: multiple clashing members declared in same class should be added to the class' scope in order to avoid downstream spurious diagnostics
Reviewed-by: jjg

src/share/classes/com/sun/tools/javac/code/Flags.java

 /*
- * Copyright (c) 1999, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2011, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -252,6 +252,11 @@ public class Flags {
      */
     public static final long EFFECTIVELY_FINAL = 1L<<42;
 
+    /**
+     * Flag that marks non-override equivalent methods with the same signature
+     */
+    public static final long CLASH = 1L<<43;
+
     /** Modifier masks.
      */
     public static final int

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

@@ -2121,7 +2121,7 @@ public class Check {
 
         public boolean accepts(Symbol s) {
             return s.kind == MTH &&
-                    (s.flags() & SYNTHETIC) == 0 &&
+                    (s.flags() & (SYNTHETIC | CLASH)) == 0 &&
                     s.isInheritedIn(site.tsym, types) &&
                     !s.isConstructor();
         }
@@ -2581,28 +2581,42 @@ public class Check {
         if (sym.owner.name == names.any) return false;
         for (Scope.Entry e = s.lookup(sym.name); e.scope == s; e = e.next()) {
             if (sym != e.sym &&
+                (e.sym.flags() & CLASH) == 0 &&
                 sym.kind == e.sym.kind &&
                 sym.name != names.error &&
                 (sym.kind != MTH || types.hasSameArgs(types.erasure(sym.type), types.erasure(e.sym.type)))) {
-                if ((sym.flags() & VARARGS) != (e.sym.flags() & VARARGS))
+                if ((sym.flags() & VARARGS) != (e.sym.flags() & VARARGS)) {
                     varargsDuplicateError(pos, sym, e.sym);
-                else if (sym.kind == MTH && !types.overrideEquivalent(sym.type, e.sym.type))
+                    return true;
+                } else if (sym.kind == MTH && !hasSameSignature(sym.type, e.sym.type)) {
                     duplicateErasureError(pos, sym, e.sym);
-                else
+                    sym.flags_field |= CLASH;
+                    return true;
+                } else {
                     duplicateError(pos, e.sym);
-                return false;
+                    return false;
+                }
             }
         }
         return true;
     }
     //where
-    /** Report duplicate declaration error.
-     */
-    void duplicateErasureError(DiagnosticPosition pos, Symbol sym1, Symbol sym2) {
-        if (!sym1.type.isErroneous() && !sym2.type.isErroneous()) {
-            log.error(pos, "name.clash.same.erasure", sym1, sym2);
+        boolean hasSameSignature(Type mt1, Type mt2) {
+            if (mt1.tag == FORALL && mt2.tag == FORALL) {
+                ForAll fa1 = (ForAll)mt1;
+                ForAll fa2 = (ForAll)mt2;
+                mt2 = types.subst(fa2, fa2.tvars, fa1.tvars);
+            }
+            return types.hasSameArgs(mt1.asMethodType(), mt2.asMethodType());
+        }
+
+        /** Report duplicate declaration error.
+         */
+        void duplicateErasureError(DiagnosticPosition pos, Symbol sym1, Symbol sym2) {
+            if (!sym1.type.isErroneous() && !sym2.type.isErroneous()) {
+                log.error(pos, "name.clash.same.erasure", sym1, sym2);
+            }
         }
-    }
 
     /** Check that single-type import is not already imported or top-level defined,
      *  but make an exception for two single-type imports which denote the same type.

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

@@ -278,7 +278,7 @@ public class Resolve {
             return true;
         else {
             Symbol s2 = ((MethodSymbol)sym).implementation(site.tsym, types, true);
-            return (s2 == null || s2 == sym ||
+            return (s2 == null || s2 == sym || sym.owner == s2.owner ||
                     s2.isPolymorphicSignatureGeneric() ||
                     !types.isSubSignature(types.memberType(site, s2), types.memberType(site, sym)));
         }
@@ -712,13 +712,14 @@ public class Resolve {
                 Type mt1 = types.memberType(site, m1);
                 Type mt2 = types.memberType(site, m2);
                 if (!types.overrideEquivalent(mt1, mt2))
-                    return new AmbiguityError(m1, m2);
+                    return ambiguityError(m1, m2);
+
                 // same signature; select (a) the non-bridge method, or
                 // (b) the one that overrides the other, or (c) the concrete
                 // one, or (d) merge both abstract signatures
-                if ((m1.flags() & BRIDGE) != (m2.flags() & BRIDGE)) {
+                if ((m1.flags() & BRIDGE) != (m2.flags() & BRIDGE))
                     return ((m1.flags() & BRIDGE) != 0) ? m2 : m1;
-                }
+
                 // if one overrides or hides the other, use it
                 TypeSymbol m1Owner = (TypeSymbol)m1.owner;
                 TypeSymbol m2Owner = (TypeSymbol)m2.owner;
@@ -738,24 +739,24 @@ public class Resolve {
                 if (m2Abstract && !m1Abstract) return m1;
                 // both abstract or both concrete
                 if (!m1Abstract && !m2Abstract)
-                    return new AmbiguityError(m1, m2);
+                    return ambiguityError(m1, m2);
                 // check that both signatures have the same erasure
                 if (!types.isSameTypes(m1.erasure(types).getParameterTypes(),
                                        m2.erasure(types).getParameterTypes()))
-                    return new AmbiguityError(m1, m2);
+                    return ambiguityError(m1, m2);
                 // both abstract, neither overridden; merge throws clause and result type
                 Symbol mostSpecific;
                 Type result2 = mt2.getReturnType();
                 if (mt2.tag == FORALL)
                     result2 = types.subst(result2, ((ForAll)mt2).tvars, ((ForAll)mt1).tvars);
-                if (types.isSubtype(mt1.getReturnType(), result2)) {
+                if (types.isSubtype(mt1.getReturnType(), result2))
                     mostSpecific = m1;
-                } else if (types.isSubtype(result2, mt1.getReturnType())) {
+                else if (types.isSubtype(result2, mt1.getReturnType()))
                     mostSpecific = m2;
-                } else {
+                else {
                     // Theoretically, this can't happen, but it is possible
                     // due to error recovery or mixing incompatible class files
-                    return new AmbiguityError(m1, m2);
+                    return ambiguityError(m1, m2);
                 }
                 MethodSymbol result = new MethodSymbol(
                         mostSpecific.flags(),
@@ -777,7 +778,7 @@ public class Resolve {
             }
             if (m1SignatureMoreSpecific) return m1;
             if (m2SignatureMoreSpecific) return m2;
-            return new AmbiguityError(m1, m2);
+            return ambiguityError(m1, m2);
         case AMBIGUOUS:
             AmbiguityError e = (AmbiguityError)m2;
             Symbol err1 = mostSpecific(m1, e.sym, env, site, allowBoxing, useVarargs);
@@ -787,9 +788,9 @@ public class Resolve {
             if (err1 instanceof AmbiguityError &&
                 err2 instanceof AmbiguityError &&
                 ((AmbiguityError)err1).sym == ((AmbiguityError)err2).sym)
-                return new AmbiguityError(m1, m2);
+                return ambiguityError(m1, m2);
             else
-                return new AmbiguityError(err1, err2);
+                return ambiguityError(err1, err2);
         default:
             throw new AssertionError();
         }
@@ -844,6 +845,14 @@ public class Resolve {
             return to;
         }
     }
+    //where
+    Symbol ambiguityError(Symbol m1, Symbol m2) {
+        if (((m1.flags() | m2.flags()) & CLASH) != 0) {
+            return (m1.flags() & CLASH) == 0 ? m1 : m2;
+        } else {
+            return new AmbiguityError(m1, m2);
+        }
+    }
 
     /** Find best qualified method matching given name, type and value
      *  arguments.

test/tools/javac/generics/6910550/T6910550a.java

+/*
+ * @test /nodynamiccopyright/
+ * @bug 6910550
+ *
+ * @summary javac 1.5.0_17 fails with incorrect error message
+ * @compile/fail/ref=T6910550a.out -XDrawDiagnostics T6910550a.java
+ *
+ */
+import java.util.*;
+
+class T6910550a {
+    void m(List<String> ls) {}
+    void m(List<Integer> li) {}
+
+    { m(Arrays.asList(12)); }
+}

test/tools/javac/generics/6910550/T6910550a.out

+T6910550a.java:13:10: compiler.err.name.clash.same.erasure: m(java.util.List<java.lang.Integer>), m(java.util.List<java.lang.String>)
+1 error

test/tools/javac/generics/6910550/T6910550b.java

+/*
+ * @test /nodynamiccopyright/
+ * @bug 6910550
+ *
+ * @summary javac 1.5.0_17 fails with incorrect error message
+ * @compile/fail/ref=T6910550b.out -XDrawDiagnostics T6910550b.java
+ *
+ */
+
+class T6910550b<X, Y, Z> {
+    void m(X x) {}
+    void m(Y y) {}
+    void m(Z y) {}
+
+    { m(null); }
+}

test/tools/javac/generics/6910550/T6910550b.out

+T6910550b.java:12:10: compiler.err.name.clash.same.erasure: m(Y), m(X)
+T6910550b.java:13:10: compiler.err.name.clash.same.erasure: m(Z), m(X)
+2 errors

test/tools/javac/generics/6910550/T6910550c.java

+/*
+ * @test /nodynamiccopyright/
+ * @bug 6910550
+ *
+ * @summary javac 1.5.0_17 fails with incorrect error message
+ * @compile/fail/ref=T6910550c.out -XDrawDiagnostics T6910550c.java
+ *
+ */
+
+class T6910550c {
+    void m(Object[] x) {}
+    void m(Object... x) {}
+
+    { m(); }
+    { m(null); }
+    { m(null, null); }
+    { m(null, null, null); }
+}

test/tools/javac/generics/6910550/T6910550c.out

+T6910550c.java:12:10: compiler.err.array.and.varargs: m(java.lang.Object...), m(java.lang.Object[]), T6910550c
+1 error

test/tools/javac/generics/6910550/T6910550d.java

+/*
+ * @test /nodynamiccopyright/
+ * @bug 6910550
+ *
+ * @summary javac 1.5.0_17 fails with incorrect error message
+ * @compile/fail/ref=T6910550d.out -XDrawDiagnostics T6910550d.java
+ *
+ */
+
+class T6910550d {
+    <X> void m(X x) {}
+    <Y> void m(Y y) {}
+
+    { m(null); }
+}

test/tools/javac/generics/6910550/T6910550d.out

+T6910550d.java:12:14: compiler.err.already.defined: <X>m(X), T6910550d
+1 error

test/tools/javac/generics/6910550/T6910550e.java

+/*
+ * @test /nodynamiccopyright/
+ * @bug 6910550
+ *
+ * @summary javac 1.5.0_17 fails with incorrect error message
+ * @compile/fail/ref=T6910550e.out -XDrawDiagnostics T6910550e.java
+ *
+ */
+
+class T6910550e {
+    static class Pair<X,Y> {}
+
+    <X> void m(Pair<X,X> x) {}
+    <X,Y> void m(Pair<X,Y> y) {}
+
+   { m(new Pair<String,String>());
+     m(new Pair<String,Integer>()); }
+}

test/tools/javac/generics/6910550/T6910550e.out

+T6910550e.java:14:16: compiler.err.name.clash.same.erasure: <X,Y>m(T6910550e.Pair<X,Y>), <X>m(T6910550e.Pair<X,X>)
+1 error