# HG changeset patch
# User mcimadamore
# Date 1316178971 -3600
# Node ID 7f15f5a11ae91601a9ba0bc9e435f901cd0fb9ad
# Parent  5dd595ab058ec0c7d69965e1b829104f698588e3
7086586: Inference producing null type argument
Summary: Inference should fail in 15.12.2.7 when inference variables with 'nulltype' upper bounds are found
Reviewed-by: dlsmith

diff -r 5dd595ab058e -r 7f15f5a11ae9 langtools/src/share/classes/com/sun/tools/javac/code/Types.java
--- a/langtools/src/share/classes/com/sun/tools/javac/code/Types.java	Wed Sep 14 18:26:57 2011 -0700
+++ b/langtools/src/share/classes/com/sun/tools/javac/code/Types.java	Fri Sep 16 14:16:11 2011 +0100
@@ -508,8 +508,13 @@
             @Override
             public Boolean visitUndetVar(UndetVar t, Type s) {
                 //todo: test against origin needed? or replace with substitution?
-                if (t == s || t.qtype == s || s.tag == ERROR || s.tag == UNKNOWN)
+                if (t == s || t.qtype == s || s.tag == ERROR || s.tag == UNKNOWN) {
                     return true;
+                } else if (s.tag == BOT) {
+                    //if 's' is 'null' there's no instantiated type U for which
+                    //U <: s (but 'null' itself, which is not a valid type)
+                    return false;
+                }
 
                 if (t.inst != null)
                     return isSubtypeNoCapture(t.inst, s); // TODO: ", warn"?
diff -r 5dd595ab058e -r 7f15f5a11ae9 langtools/test/tools/javac/Diagnostics/6862608/T6862608a.out
--- a/langtools/test/tools/javac/Diagnostics/6862608/T6862608a.out	Wed Sep 14 18:26:57 2011 -0700
+++ b/langtools/test/tools/javac/Diagnostics/6862608/T6862608a.out	Fri Sep 16 14:16:11 2011 +0100
@@ -1,3 +1,3 @@
-T6862608a.java:19:41: compiler.err.prob.found.req: (compiler.misc.incompatible.types.1: (compiler.misc.infer.no.conforming.instance.exists: T, java.util.Comparator<T>, java.util.Comparator<java.lang.String>)), <T>java.util.Comparator<T>, java.util.Comparator<java.lang.String>
+T6862608a.java:19:33: compiler.err.cant.apply.symbol.1: kindname.method, compound, java.lang.Iterable<? extends java.util.Comparator<? super T>>, java.util.List<java.util.Comparator<?>>, kindname.class, T6862608a, (compiler.misc.infer.no.conforming.assignment.exists: T, java.util.List<java.util.Comparator<?>>, java.lang.Iterable<? extends java.util.Comparator<? super T>>)
 - compiler.misc.where.description.typevar: T,{(compiler.misc.where.typevar: T, java.lang.Object, kindname.method, <T>compound(java.lang.Iterable<? extends java.util.Comparator<? super T>>))}
 1 error
diff -r 5dd595ab058e -r 7f15f5a11ae9 langtools/test/tools/javac/generics/inference/6638712/T6638712a.out
--- a/langtools/test/tools/javac/generics/inference/6638712/T6638712a.out	Wed Sep 14 18:26:57 2011 -0700
+++ b/langtools/test/tools/javac/generics/inference/6638712/T6638712a.out	Fri Sep 16 14:16:11 2011 +0100
@@ -1,2 +1,2 @@
-T6638712a.java:16:41: compiler.err.prob.found.req: (compiler.misc.incompatible.types.1: (compiler.misc.infer.no.conforming.instance.exists: T, java.util.Comparator<T>, java.util.Comparator<java.lang.String>)), <T>java.util.Comparator<T>, java.util.Comparator<java.lang.String>
+T6638712a.java:16:33: compiler.err.cant.apply.symbol.1: kindname.method, compound, java.lang.Iterable<? extends java.util.Comparator<? super T>>, java.util.List<java.util.Comparator<?>>, kindname.class, T6638712a, (compiler.misc.infer.no.conforming.assignment.exists: T, java.util.List<java.util.Comparator<?>>, java.lang.Iterable<? extends java.util.Comparator<? super T>>)
 1 error
diff -r 5dd595ab058e -r 7f15f5a11ae9 langtools/test/tools/javac/generics/inference/7086586/T7086586.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/test/tools/javac/generics/inference/7086586/T7086586.java	Fri Sep 16 14:16:11 2011 +0100
@@ -0,0 +1,19 @@
+/**
+ * @test /nodynamiccopyright/
+ * @bug 7086586
+ * @summary Inference producing null type argument
+ * @compile/fail/ref=T7086586.out -XDrawDiagnostics T7086586.java
+ */
+import java.util.List;
+
+class T7086586 {
+
+    <T> List<T> m(List<? super T> dummy) { return null; }
+
+    void test(List<?> l) {
+        String s = m(l).get(0);
+        Number n = m(l).get(0);
+        Exception e = m(l).get(0);
+        m(l).nonExistentMethod();
+    }
+}
diff -r 5dd595ab058e -r 7f15f5a11ae9 langtools/test/tools/javac/generics/inference/7086586/T7086586.out
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/test/tools/javac/generics/inference/7086586/T7086586.out	Fri Sep 16 14:16:11 2011 +0100
@@ -0,0 +1,5 @@
+T7086586.java:14:20: compiler.err.cant.apply.symbol.1: kindname.method, m, java.util.List<? super T>, java.util.List<compiler.misc.type.captureof: 1, ?>, kindname.class, T7086586, (compiler.misc.infer.no.conforming.assignment.exists: T, java.util.List<compiler.misc.type.captureof: 1, ?>, java.util.List<? super T>)
+T7086586.java:15:20: compiler.err.cant.apply.symbol.1: kindname.method, m, java.util.List<? super T>, java.util.List<compiler.misc.type.captureof: 1, ?>, kindname.class, T7086586, (compiler.misc.infer.no.conforming.assignment.exists: T, java.util.List<compiler.misc.type.captureof: 1, ?>, java.util.List<? super T>)
+T7086586.java:16:23: compiler.err.cant.apply.symbol.1: kindname.method, m, java.util.List<? super T>, java.util.List<compiler.misc.type.captureof: 1, ?>, kindname.class, T7086586, (compiler.misc.infer.no.conforming.assignment.exists: T, java.util.List<compiler.misc.type.captureof: 1, ?>, java.util.List<? super T>)
+T7086586.java:17:9: compiler.err.cant.apply.symbol.1: kindname.method, m, java.util.List<? super T>, java.util.List<compiler.misc.type.captureof: 1, ?>, kindname.class, T7086586, (compiler.misc.infer.no.conforming.assignment.exists: T, java.util.List<compiler.misc.type.captureof: 1, ?>, java.util.List<? super T>)
+4 errors
diff -r 5dd595ab058e -r 7f15f5a11ae9 langtools/test/tools/javac/generics/inference/7086586/T7086586b.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/test/tools/javac/generics/inference/7086586/T7086586b.java	Fri Sep 16 14:16:11 2011 +0100
@@ -0,0 +1,54 @@
+/*
+ * 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 7086586
+ *
+ * @summary Inference producing null type argument
+ */
+import java.util.List;
+
+public class T7086586b {
+
+    int assertionCount = 0;
+
+    void assertTrue(boolean cond) {
+        if (!cond) {
+            throw new AssertionError();
+        }
+        assertionCount++;
+    }
+
+    <T> void m(List<? super T> dummy) { assertTrue(false); }
+    <T> void m(Object dummy) { assertTrue(true); }
+
+    void test(List<?> l) {
+        m(l);
+        assertTrue(assertionCount == 1);
+    }
+
+    public static void main(String[] args) {
+        new T7086586b().test(null);
+    }
+}