8023389: Javac fails to infer type for lambda used with intersection type and wildcards
Reviewed-by: jjg, vromero
Contributed-by: maurizio.cimadamore@oracle.com
--- a/langtools/src/share/classes/com/sun/tools/javac/comp/Attr.java Mon Sep 02 22:44:06 2013 +0100
+++ b/langtools/src/share/classes/com/sun/tools/javac/comp/Attr.java Tue Sep 03 23:31:33 2013 +0100
@@ -2319,30 +2319,37 @@
boolean needsRecovery =
resultInfo.checkContext.deferredAttrContext().mode == DeferredAttr.AttrMode.CHECK;
try {
- Type target = pt();
+ Type currentTarget = pt();
List<Type> explicitParamTypes = null;
if (that.paramKind == JCLambda.ParameterKind.EXPLICIT) {
//attribute lambda parameters
attribStats(that.params, localEnv);
explicitParamTypes = TreeInfo.types(that.params);
- target = infer.instantiateFunctionalInterface(that, target, explicitParamTypes, resultInfo.checkContext);
}
Type lambdaType;
if (pt() != Type.recoveryType) {
- target = targetChecker.visit(target, that);
- lambdaType = types.findDescriptorType(target);
+ /* We need to adjust the target. If the target is an
+ * intersection type, for example: SAM & I1 & I2 ...
+ * the target will be updated to SAM
+ */
+ currentTarget = targetChecker.visit(currentTarget, that);
+ if (explicitParamTypes != null) {
+ currentTarget = infer.instantiateFunctionalInterface(that,
+ currentTarget, explicitParamTypes, resultInfo.checkContext);
+ }
+ lambdaType = types.findDescriptorType(currentTarget);
} else {
- target = Type.recoveryType;
+ currentTarget = Type.recoveryType;
lambdaType = fallbackDescriptorType(that);
}
- setFunctionalInfo(localEnv, that, pt(), lambdaType, target, resultInfo.checkContext);
+ setFunctionalInfo(localEnv, that, pt(), lambdaType, currentTarget, resultInfo.checkContext);
if (lambdaType.hasTag(FORALL)) {
//lambda expression target desc cannot be a generic method
resultInfo.checkContext.report(that, diags.fragment("invalid.generic.lambda.target",
- lambdaType, kindName(target.tsym), target.tsym));
+ lambdaType, kindName(currentTarget.tsym), currentTarget.tsym));
result = that.type = types.createErrorType(pt());
return;
}
@@ -2376,7 +2383,7 @@
if (arityMismatch) {
resultInfo.checkContext.report(that, diags.fragment("incompatible.arg.types.in.lambda"));
- result = that.type = types.createErrorType(target);
+ result = that.type = types.createErrorType(currentTarget);
return;
}
}
@@ -2403,7 +2410,7 @@
attribStats(body.stats, localEnv);
}
- result = check(that, target, VAL, resultInfo);
+ result = check(that, currentTarget, VAL, resultInfo);
boolean isSpeculativeRound =
resultInfo.checkContext.deferredAttrContext().mode == DeferredAttr.AttrMode.SPECULATIVE;
@@ -2414,9 +2421,9 @@
checkLambdaCompatible(that, lambdaType, resultInfo.checkContext, isSpeculativeRound);
if (!isSpeculativeRound) {
- checkAccessibleTypes(that, localEnv, resultInfo.checkContext.inferenceContext(), lambdaType, target);
+ checkAccessibleTypes(that, localEnv, resultInfo.checkContext.inferenceContext(), lambdaType, currentTarget);
}
- result = check(that, target, VAL, resultInfo);
+ result = check(that, currentTarget, VAL, resultInfo);
} catch (Types.FunctionDescriptorLookupError ex) {
JCDiagnostic cause = ex.getDiagnostic();
resultInfo.checkContext.report(that, cause);
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/test/tools/javac/lambda/8023389/T8023389.java Tue Sep 03 23:31:33 2013 +0100
@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2013, 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 8023389
+ * @summary Javac fails to infer type for lambda used with intersection type and wildcards
+ * @compile T8023389.java
+ */
+public class T8023389 {
+
+ static class U1 {}
+ static class X1 extends U1 {}
+
+ interface I { }
+
+ interface SAM<T> {
+ void m(T t);
+ }
+
+ /* Strictly speaking only the second of the following declarations provokes the bug.
+ * But the first line is also a useful test case.
+ */
+ SAM<? extends U1> sam1 = (SAM<? extends U1>) (X1 x) -> { };
+ SAM<? extends U1> sam2 = (SAM<? extends U1> & I) (X1 x) -> { };
+}