graph inference: infer from non-eq type bound

2026-08-26 00:11:26 +07:00 · 2013-02-20 18:09:44 +01:00
parent 87464bfa04
commit 35c349430a
3 changed files with 85 additions and 0 deletions
@@ -0,0 +1,68 @@
+import java.util.*;
+
+public class ConcurrentCollectors {
+    static class Test1 {
+        static <T, K, D, M1 extends ConcurrentMap<K, D>> C<T, M1> groupingBy(F<M1> f,
+                                                                             C<T, D> c,
+                                                                             BiConsumer<M1, T> consumer) {
+            return new CImpl<>(f, consumer, arg(c.getOp()));
+        }
+
+        static <K, V, M2 extends Map<K, V>> BiOp<M2> arg(BiOp<V> op) {
+            return null;
+        }
+    }
+
+    static class Test2 {
+        static <T, K, D, M1 extends ConcurrentMap<K, D>> C<T, M1> groupingBy(F<M1> f,
+                                                                             C<T, D> c,
+                                                                             BiConsumer<M1, T> consumer) {
+            return new CImpl<>(f, consumer, arg(c.getOp()));
+        }
+
+        static <K, V, M2 extends ConcurrentMap<K, V>> BiOp<M2> arg(BiOp<V> op) {
+            return null;
+        }
+    }
+
+    static class Test3 {
+        static <T, K, D, M1 extends Map<K, D>> C<T, M1> groupingBy(F<M1> f,
+                                                                   C<T, D> c,
+                                                                   BiConsumer<M1, T> consumer) {
+            return new CImpl<>(f, consumer, <error descr="Inferred type 'M1' for type parameter 'M2' is not within its bound; should implement 'ConcurrentCollectors.ConcurrentMap<java.lang.Object,D>'">arg(c.getOp())</error>);
+        }
+
+        static <K, V, M2 extends ConcurrentMap<K, V>> BiOp<M2> arg(BiOp<V> op) {
+            return null;
+        }
+    }
+
+
+    interface C<T, R> {
+        BiOp<R> getOp();
+    }
+
+    interface F<T> {}
+
+
+    static class CImpl<T, R> implements C<T, R> {
+        CImpl(F<R> f,
+              BiConsumer<R, T> consumer,
+              BiOp<R> op) {
+        }
+
+        @Override
+        public BiOp<R> getOp() {
+            return null;
+        }
+    }
+
+    interface BiFun<T, U, R> { }
+
+    interface BiOp<T> extends BiFun<T, T, T> {
+    }
+
+    interface BiConsumer<T, U> {}
+    
+    interface ConcurrentMap<A, B> extends Map<A, B> {}
+}