7062745: Regression: difference in overload resolution when two methods are maximally specific
Summary: Fix most specific when two methods are maximally specific and only one has non-raw return type
Reviewed-by: jjg, dlsmith
--- a/langtools/src/share/classes/com/sun/tools/javac/comp/Resolve.java Fri Jul 22 21:31:14 2011 -0700
+++ b/langtools/src/share/classes/com/sun/tools/javac/comp/Resolve.java Wed Jul 27 19:00:53 2011 +0100
@@ -767,16 +767,13 @@
m2.erasure(types).getParameterTypes()))
return ambiguityError(m1, m2);
// both abstract, neither overridden; merge throws clause and result type
- Symbol mostSpecific;
- if (types.returnTypeSubstitutable(mt1, mt2))
- mostSpecific = m1;
- else if (types.returnTypeSubstitutable(mt2, mt1))
- mostSpecific = m2;
- else {
+ Type mst = mostSpecificReturnType(mt1, mt2);
+ if (mst == null) {
// Theoretically, this can't happen, but it is possible
// due to error recovery or mixing incompatible class files
return ambiguityError(m1, m2);
}
+ Symbol mostSpecific = mst == mt1 ? m1 : m2;
List<Type> allThrown = chk.intersect(mt1.getThrownTypes(), mt2.getThrownTypes());
Type newSig = types.createMethodTypeWithThrown(mostSpecific.type, allThrown);
MethodSymbol result = new MethodSymbol(
@@ -859,6 +856,28 @@
}
}
//where
+ Type mostSpecificReturnType(Type mt1, Type mt2) {
+ Type rt1 = mt1.getReturnType();
+ Type rt2 = mt2.getReturnType();
+
+ if (mt1.tag == FORALL && mt2.tag == FORALL) {
+ //if both are generic methods, adjust return type ahead of subtyping check
+ rt1 = types.subst(rt1, mt1.getTypeArguments(), mt2.getTypeArguments());
+ }
+ //first use subtyping, then return type substitutability
+ if (types.isSubtype(rt1, rt2)) {
+ return mt1;
+ } else if (types.isSubtype(rt2, rt1)) {
+ return mt2;
+ } else if (types.returnTypeSubstitutable(mt1, mt2)) {
+ return mt1;
+ } else if (types.returnTypeSubstitutable(mt2, mt1)) {
+ return mt2;
+ } else {
+ return null;
+ }
+ }
+ //where
Symbol ambiguityError(Symbol m1, Symbol m2) {
if (((m1.flags() | m2.flags()) & CLASH) != 0) {
return (m1.flags() & CLASH) == 0 ? m1 : m2;
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/test/tools/javac/generics/rawOverride/7062745/GenericOverrideTest.java Wed Jul 27 19:00:53 2011 +0100
@@ -0,0 +1,286 @@
+/*
+ * Copyright (c) 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
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 7062745
+ * @summary Regression: difference in overload resolution when two methods are maximally specific
+ */
+
+import com.sun.source.util.JavacTask;
+import java.net.URI;
+import java.util.Arrays;
+import javax.tools.Diagnostic;
+import javax.tools.JavaCompiler;
+import javax.tools.JavaFileObject;
+import javax.tools.SimpleJavaFileObject;
+import javax.tools.StandardJavaFileManager;
+import javax.tools.ToolProvider;
+
+public class GenericOverrideTest {
+
+ static int checkCount = 0;
+
+ enum SignatureKind {
+ NON_GENERIC(""),
+ GENERIC("<X>");
+
+ String paramStr;
+
+ private SignatureKind(String paramStr) {
+ this.paramStr = paramStr;
+ }
+ }
+
+ enum ReturnTypeKind {
+ LIST("List"),
+ ARRAYLIST("ArrayList");
+
+ String retStr;
+
+ private ReturnTypeKind(String retStr) {
+ this.retStr = retStr;
+ }
+
+ boolean moreSpecificThan(ReturnTypeKind that) {
+ switch (this) {
+ case LIST:
+ return that == this;
+ case ARRAYLIST:
+ return that == LIST || that == ARRAYLIST;
+ default: throw new AssertionError("Unexpected ret kind: " + this);
+ }
+ }
+ }
+
+ enum TypeArgumentKind {
+ NONE(""),
+ UNBOUND("<?>"),
+ INTEGER("<Number>"),
+ NUMBER("<Integer>"),
+ TYPEVAR("<X>");
+
+ String typeargStr;
+
+ private TypeArgumentKind(String typeargStr) {
+ this.typeargStr = typeargStr;
+ }
+
+ boolean compatibleWith(SignatureKind sig) {
+ switch (this) {
+ case TYPEVAR: return sig != SignatureKind.NON_GENERIC;
+ default: return true;
+ }
+ }
+
+ boolean moreSpecificThan(TypeArgumentKind that, boolean strict) {
+ switch (this) {
+ case NONE:
+ return that == this || !strict;
+ case UNBOUND:
+ return that == this || that == NONE;
+ case INTEGER:
+ case NUMBER:
+ case TYPEVAR:
+ return that == this || that == NONE || that == UNBOUND;
+ default: throw new AssertionError("Unexpected typearg kind: " + this);
+ }
+ }
+
+ boolean assignableTo(TypeArgumentKind that, SignatureKind sig) {
+ switch (this) {
+ case NONE:
+ //this case needs to workaround to javac's impl of 15.12.2.8 being too strict
+ //ideally should be just 'return true' (see 7067746)
+ return sig == SignatureKind.NON_GENERIC || that == NONE;
+ case UNBOUND:
+ return that == this || that == NONE;
+ case INTEGER:
+ case NUMBER:
+ return that == this || that == NONE || that == UNBOUND;
+ case TYPEVAR:
+ return true;
+ default: throw new AssertionError("Unexpected typearg kind: " + this);
+ }
+ }
+ }
+
+ public static void main(String... args) throws Exception {
+
+ //create default shared JavaCompiler - reused across multiple compilations
+ JavaCompiler comp = ToolProvider.getSystemJavaCompiler();
+ StandardJavaFileManager fm = comp.getStandardFileManager(null, null, null);
+
+ for (SignatureKind sig1 : SignatureKind.values()) {
+ for (ReturnTypeKind rt1 : ReturnTypeKind.values()) {
+ for (TypeArgumentKind ta1 : TypeArgumentKind.values()) {
+ if (!ta1.compatibleWith(sig1)) continue;
+ for (SignatureKind sig2 : SignatureKind.values()) {
+ for (ReturnTypeKind rt2 : ReturnTypeKind.values()) {
+ for (TypeArgumentKind ta2 : TypeArgumentKind.values()) {
+ if (!ta2.compatibleWith(sig2)) continue;
+ for (ReturnTypeKind rt3 : ReturnTypeKind.values()) {
+ for (TypeArgumentKind ta3 : TypeArgumentKind.values()) {
+ if (!ta3.compatibleWith(SignatureKind.NON_GENERIC)) continue;
+ new GenericOverrideTest(sig1, rt1, ta1, sig2, rt2, ta2, rt3, ta3).run(comp, fm);
+ }
+ }
+ }
+ }
+ }
+ }
+ }
+ }
+ System.out.println("Total check executed: " + checkCount);
+ }
+
+ SignatureKind sig1, sig2;
+ ReturnTypeKind rt1, rt2, rt3;
+ TypeArgumentKind ta1, ta2, ta3;
+ JavaSource source;
+ DiagnosticChecker diagChecker;
+
+ GenericOverrideTest(SignatureKind sig1, ReturnTypeKind rt1, TypeArgumentKind ta1,
+ SignatureKind sig2, ReturnTypeKind rt2, TypeArgumentKind ta2, ReturnTypeKind rt3, TypeArgumentKind ta3) {
+ this.sig1 = sig1;
+ this.sig2 = sig2;
+ this.rt1 = rt1;
+ this.rt2 = rt2;
+ this.rt3 = rt3;
+ this.ta1 = ta1;
+ this.ta2 = ta2;
+ this.ta3 = ta3;
+ this.source = new JavaSource();
+ this.diagChecker = new DiagnosticChecker();
+ }
+
+ class JavaSource extends SimpleJavaFileObject {
+
+ String template = "import java.util.*;\n" +
+ "interface A { #S1 #R1#TA1 m(); }\n" +
+ "interface B { #S2 #R2#TA2 m(); }\n" +
+ "interface AB extends A, B {}\n" +
+ "class Test {\n" +
+ " void test(AB ab) { #R3#TA3 n = ab.m(); }\n" +
+ "}";
+
+ String source;
+
+ public JavaSource() {
+ super(URI.create("myfo:/Test.java"), JavaFileObject.Kind.SOURCE);
+ source = template.replace("#S1", sig1.paramStr).
+ replace("#S2", sig2.paramStr).
+ replace("#R1", rt1.retStr).
+ replace("#R2", rt2.retStr).
+ replace("#R3", rt3.retStr).
+ replace("#TA1", ta1.typeargStr).
+ replace("#TA2", ta2.typeargStr).
+ replace("#TA3", ta3.typeargStr);
+ }
+
+ @Override
+ public CharSequence getCharContent(boolean ignoreEncodingErrors) {
+ return source;
+ }
+ }
+
+ void run(JavaCompiler tool, StandardJavaFileManager fm) throws Exception {
+ JavacTask ct = (JavacTask)tool.getTask(null, fm, diagChecker,
+ null, null, Arrays.asList(source));
+ try {
+ ct.analyze();
+ } catch (Throwable ex) {
+ throw new AssertionError("Error thron when compiling the following code:\n" + source.getCharContent(true));
+ }
+ check();
+ }
+
+ void check() {
+ checkCount++;
+
+ boolean errorExpected = false;
+ int mostSpecific = 0;
+
+ //first check that either |R1| <: |R2| or |R2| <: |R1|
+ if (rt1 != rt2) {
+ if (!rt1.moreSpecificThan(rt2) &&
+ !rt2.moreSpecificThan(rt1)) {
+ errorExpected = true;
+ } else {
+ mostSpecific = rt1.moreSpecificThan(rt2) ? 1 : 2;
+ }
+ }
+
+ //check that either TA1 <= TA2 or TA2 <= TA1 (unless most specific return found above is raw)
+ if (!errorExpected) {
+ if (ta1 != ta2) {
+ boolean useStrictCheck = ta1.moreSpecificThan(ta2, true) || ta2.moreSpecificThan(ta1, true);
+ if (!ta1.moreSpecificThan(ta2, useStrictCheck) &&
+ !ta2.moreSpecificThan(ta1, useStrictCheck)) {
+ errorExpected = true;
+ } else {
+ int mostSpecific2 = ta1.moreSpecificThan(ta2, useStrictCheck) ? 1 : 2;
+ if (mostSpecific != 0 && mostSpecific2 != mostSpecific) {
+ errorExpected = mostSpecific == 1 ? ta1 != TypeArgumentKind.NONE : ta2 != TypeArgumentKind.NONE;
+ } else {
+ mostSpecific = mostSpecific2;
+ }
+ }
+ } else if (mostSpecific == 0) {
+ //when no signature is better than the other, an arbitrary choice
+ //must be made - javac always picks the second signature
+ mostSpecific = 2;
+ }
+ }
+
+ //finally, check that most specific return type is compatible with expected type
+ if (!errorExpected) {
+ ReturnTypeKind msrt = mostSpecific == 1 ? rt1 : rt2;
+ TypeArgumentKind msta = mostSpecific == 1 ? ta1 : ta2;
+ SignatureKind mssig = mostSpecific == 1 ? sig1 : sig2;
+
+ if (!msrt.moreSpecificThan(rt3) ||
+ !msta.assignableTo(ta3, mssig)) {
+ errorExpected = true;
+ }
+ }
+
+ if (errorExpected != diagChecker.errorFound) {
+ throw new Error("invalid diagnostics for source:\n" +
+ source.getCharContent(true) +
+ "\nFound error: " + diagChecker.errorFound +
+ "\nExpected error: " + errorExpected);
+ }
+ }
+
+ static class DiagnosticChecker implements javax.tools.DiagnosticListener<JavaFileObject> {
+
+ boolean errorFound;
+
+ public void report(Diagnostic<? extends JavaFileObject> diagnostic) {
+ if (diagnostic.getKind() == Diagnostic.Kind.ERROR) {
+ errorFound = true;
+ }
+ }
+ }
+}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/test/tools/javac/generics/rawOverride/7062745/T7062745neg.java Wed Jul 27 19:00:53 2011 +0100
@@ -0,0 +1,18 @@
+/*
+ * @test /nodynamiccopyright/
+ * @bug 7062745
+ * @summary Regression: difference in overload resolution when two methods are maximally specific
+ * @compile/fail/ref=T7062745neg.out -XDrawDiagnostics T7062745neg.java
+ */
+
+import java.util.*;
+
+class T7062745neg {
+ interface A { List<Number> getList(); }
+ interface B { ArrayList getList(); }
+ interface AB extends A, B {}
+
+ void test(AB ab) {
+ Number n = ab.getList().get(1);
+ }
+}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/test/tools/javac/generics/rawOverride/7062745/T7062745neg.out Wed Jul 27 19:00:53 2011 +0100
@@ -0,0 +1,2 @@
+T7062745neg.java:16:36: compiler.err.prob.found.req: (compiler.misc.incompatible.types), java.lang.Object, java.lang.Number
+1 error
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/test/tools/javac/generics/rawOverride/7062745/T7062745pos.java Wed Jul 27 19:00:53 2011 +0100
@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) 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
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 7062745
+ * @summary Regression: difference in overload resolution when two methods are maximally specific
+ *
+ * @compile T7062745pos.java
+ */
+
+import java.util.*;
+
+class T7062745pos {
+ interface A { List<Number> getList(); }
+ interface B { List getList(); }
+ interface AB extends A, B {}
+
+ void test(AB ab) {
+ Number n = ab.getList().get(1);
+ }
+}