8009131: Overload: javac should discard methods that lead to errors in lambdas...

8009131: Overload: javac should discard methods that lead to errors in lambdas with implicit parameter types
Summary: Lambdas that have errors in their bodies should make enclosing overload resolution fail
Reviewed-by: jjg

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

@@ -2340,11 +2340,34 @@ public class Attr extends JCTree.Visitor {
                 new ResultInfo(VAL, lambdaType.getReturnType(), funcContext);
             localEnv.info.returnResult = bodyResultInfo;
 
-            if (that.getBodyKind() == JCLambda.BodyKind.EXPRESSION) {
-                attribTree(that.getBody(), localEnv, bodyResultInfo);
-            } else {
-                JCBlock body = (JCBlock)that.body;
-                attribStats(body.stats, localEnv);
+            Log.DeferredDiagnosticHandler lambdaDeferredHandler = new Log.DeferredDiagnosticHandler(log);
+            try {
+                if (that.getBodyKind() == JCLambda.BodyKind.EXPRESSION) {
+                    attribTree(that.getBody(), localEnv, bodyResultInfo);
+                } else {
+                    JCBlock body = (JCBlock)that.body;
+                    attribStats(body.stats, localEnv);
+                }
+
+                if (resultInfo.checkContext.deferredAttrContext().mode == AttrMode.SPECULATIVE) {
+                    //check for errors in lambda body
+                    for (JCDiagnostic deferredDiag : lambdaDeferredHandler.getDiagnostics()) {
+                        if (deferredDiag.getKind() == JCDiagnostic.Kind.ERROR) {
+                            resultInfo.checkContext
+                                    .report(that, diags.fragment("bad.arg.types.in.lambda", TreeInfo.types(that.params)));
+                            //we mark the lambda as erroneous - this is crucial in the recovery step
+                            //as parameter-dependent type error won't be reported in that stage,
+                            //meaning that a lambda will be deemed erroeneous only if there is
+                            //a target-independent error (which will cause method diagnostic
+                            //to be skipped).
+                            result = that.type = types.createErrorType(target);
+                            return;
+                        }
+                    }
+                }
+            } finally {
+                lambdaDeferredHandler.reportDeferredDiagnostics();
+                log.popDiagnosticHandler(lambdaDeferredHandler);
             }
 
             result = check(that, target, VAL, resultInfo);

src/share/classes/com/sun/tools/javac/resources/compiler.properties

@@ -731,6 +731,11 @@ compiler.misc.incompatible.arg.types.in.lambda=\
 compiler.misc.incompatible.arg.types.in.mref=\
     incompatible parameter types in method reference
 
+# 0: list of type
+compiler.misc.bad.arg.types.in.lambda=\
+    cannot type-check lambda expression with inferred parameter types\n\
+    inferred types: {0}
+
 compiler.err.new.not.allowed.in.annotation=\
     ''new'' not allowed in an annotation
 

test/tools/javac/diags/examples/BadArgTypesInLambda.java

+/*
+ * 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.
+ */
+
+// key: compiler.err.cant.apply.symbol
+// key: compiler.misc.no.conforming.assignment.exists
+// key: compiler.misc.bad.arg.types.in.lambda
+
+class BadArgTypesInLambda {
+    interface SAM {
+        void m(Integer i);
+    }
+
+    void g(SAM s) { }
+
+    void test() {
+        g(x->{ String s = x; });
+    }
+}

test/tools/javac/lambda/BadRecovery.out

-BadRecovery.java:17:9: compiler.err.cant.apply.symbol: kindname.method, m, BadRecovery.SAM1, @369, kindname.class, BadRecovery, (compiler.misc.no.conforming.assignment.exists: (compiler.misc.incompatible.arg.types.in.lambda))
 BadRecovery.java:17:77: compiler.err.cant.resolve.location: kindname.variable, f, , , (compiler.misc.location: kindname.class, BadRecovery, null)
-2 errors
+1 error

test/tools/javac/lambda/TargetType01.java

 /*
- * Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2011, 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
@@ -23,11 +23,10 @@
 
 /*
  * @test
- * @bug 8003280
+ * @bug 8003280 8009131
  * @summary Add lambda tests
  *  check nested case of overload resolution and lambda parameter inference
- * @author  Maurizio Cimadamore
- * @compile/fail/ref=TargetType01.out -XDrawDiagnostics TargetType01.java
+ * @compile TargetType01.java
  */
 
 class TargetType01 {

test/tools/javac/lambda/TargetType01.out

-TargetType01.java:46:9: compiler.err.ref.ambiguous: M, kindname.method, M(TargetType01.F_I_I), TargetType01, kindname.method, M(TargetType01.F_S_S), TargetType01
-TargetType01.java:46:26: compiler.err.ref.ambiguous: M, kindname.method, M(TargetType01.F_I_I), TargetType01, kindname.method, M(TargetType01.F_S_S), TargetType01
-2 errors

test/tools/javac/lambda/TargetType43.out

 TargetType43.java:13:20: compiler.err.prob.found.req: (compiler.misc.not.a.functional.intf: java.lang.Object)
 TargetType43.java:13:30: compiler.err.cant.resolve.location: kindname.class, NonExistentClass, , , (compiler.misc.location: kindname.class, TargetType43, null)
-TargetType43.java:14:9: compiler.err.cant.apply.symbol: kindname.method, m, java.lang.Object, @359, kindname.class, TargetType43, (compiler.misc.no.conforming.assignment.exists: (compiler.misc.not.a.functional.intf: java.lang.Object))
 TargetType43.java:14:21: compiler.err.cant.resolve.location: kindname.class, NonExistentClass, , , (compiler.misc.location: kindname.class, TargetType43, null)
-4 errors
+3 errors

test/tools/javac/lambda/TargetType66.java

+/*
+ * @test /nodynamiccopyright/
+ * @bug 8009131
+ * @summary Overload: javac should discard methods that lead to errors in lambdas with implicit parameter types
+ * @compile/fail/ref=TargetType66.out -XDrawDiagnostics TargetType66.java
+ */
+class TargetType66 {
+    interface SAM1 {
+        void m(String s);
+    }
+
+    interface SAM2 {
+        void m(Integer s);
+    }
+
+    void g(SAM1 s1) { }
+    void g(SAM2 s2) { }
+
+    void test() {
+        g(x->{ String s = x; }); //g(SAM1)
+        g(x->{ Integer i = x; }); //g(SAM2)
+        g(x->{ Object o = x; }); //ambiguous
+        g(x->{ Character c = x; }); //error: inapplicable methods
+        g(x->{ Character c = ""; }); //error: incompatible types
+    }
+}

test/tools/javac/lambda/TargetType66.out

+TargetType66.java:22:9: compiler.err.ref.ambiguous: g, kindname.method, g(TargetType66.SAM1), TargetType66, kindname.method, g(TargetType66.SAM2), TargetType66
+TargetType66.java:23:9: compiler.err.cant.apply.symbols: kindname.method, g, @578,{(compiler.misc.inapplicable.method: kindname.method, TargetType66, g(TargetType66.SAM1), (compiler.misc.no.conforming.assignment.exists: (compiler.misc.bad.arg.types.in.lambda: java.lang.String))),(compiler.misc.inapplicable.method: kindname.method, TargetType66, g(TargetType66.SAM2), (compiler.misc.no.conforming.assignment.exists: (compiler.misc.bad.arg.types.in.lambda: java.lang.Integer)))}
+TargetType66.java:24:30: compiler.err.prob.found.req: (compiler.misc.inconvertible.types: java.lang.String, java.lang.Character)
+3 errors