#775 Fix mapping method type matching for lower-bounded target type.

processor/src/main/java/org/mapstruct/ap/internal/model/source/MethodMatcher.java

@@ -224,17 +224,32 @@ public class MethodMatcher {
     }
 
     private enum Assignability {
-        VISITED_ASSIGNABLE_FROM, VISITED_ASSIGNABLE_TO
+        VISITED_ASSIGNABLE_FROM, VISITED_ASSIGNABLE_TO;
+
+        Assignability invert() {
+            return this == VISITED_ASSIGNABLE_FROM
+                            ? VISITED_ASSIGNABLE_TO
+                            : VISITED_ASSIGNABLE_FROM;
+        }
     }
 
     private class TypeMatcher extends SimpleTypeVisitor6<Boolean, TypeMirror> {
         private final Assignability assignability;
         private final Map<TypeVariable, TypeMirror> genericTypesMap;
+        private final TypeMatcher inverse;
 
         TypeMatcher(Assignability assignability, Map<TypeVariable, TypeMirror> genericTypesMap) {
             super( Boolean.FALSE ); // default value
             this.assignability = assignability;
             this.genericTypesMap = genericTypesMap;
+            this.inverse = new TypeMatcher( this, genericTypesMap );
+        }
+
+        TypeMatcher(TypeMatcher inverse, Map<TypeVariable, TypeMirror> genericTypesMap) {
+            super( Boolean.FALSE ); // default value
+            this.assignability = inverse.assignability.invert();
+            this.genericTypesMap = genericTypesMap;
+            this.inverse = inverse;
         }
 
         @Override
@@ -262,7 +277,7 @@ public class MethodMatcher {
                 if ( assignabilityMatches( t, t1 )
                     && t.getTypeArguments().size() == t1.getTypeArguments().size() ) {
                     for ( int i = 0; i < t.getTypeArguments().size(); i++ ) {
-                        if ( !t.getTypeArguments().get( i ).accept( this, t1.getTypeArguments().get( i ) ) ) {
+                        if ( !visit( t.getTypeArguments().get( i ), t1.getTypeArguments().get( i ) ) ) {
                             return Boolean.FALSE;
                         }
                     }
@@ -272,6 +287,9 @@ public class MethodMatcher {
                     return Boolean.FALSE;
                 }
             }
+            else if ( p.getKind() == TypeKind.WILDCARD ) {
+                return inverse.visit( p, t ); // inverse, as we switch the params
+            }
             else {
                 return Boolean.FALSE;
             }
@@ -326,7 +344,7 @@ public class MethodMatcher {
                     case DECLARED:
                         // for example method: String method(? extends String)
                         // isSubType checks range [subtype, type], e.g. isSubtype [Object, String]==true
-                        return typeUtils.isSubtype( p, extendsBound );
+                        return visit( extendsBound, p );
 
                     case TYPEVAR:
                         // for example method: <T extends String & Serializable> T method(? extends T)
@@ -401,7 +419,7 @@ public class MethodMatcher {
      * @return true if within bounds
      */
     private boolean isWithinBounds(TypeMirror t, TypeParameterElement tpe) {
-        List<? extends TypeMirror> bounds = tpe.getBounds();
+        List<? extends TypeMirror> bounds = tpe != null ? tpe.getBounds() : null;
         if ( t != null && bounds != null ) {
             for ( TypeMirror bound : bounds ) {
                 if ( !( bound.getKind() == TypeKind.DECLARED && typeUtils.isSubtype( t, bound ) ) ) {

processor/src/test/java/org/mapstruct/ap/test/bugs/_775/IterableWithBoundedElementTypeTest.java

@@ -32,6 +32,8 @@ import org.mapstruct.ap.testutil.runner.AnnotationProcessorTestRunner;
  * Verifies:
  * <ul>
  * <li>For target properties of type {@link Iterable}, a forged method can be created.
+ * <li>For target properties of type {@code Iterable<? extends Integer>}, a custom mapping method that returns
+ * {@code List<Integer>} is chosen as property mapping method.
  * </ul>
  *
  * @author Andreas Gudian
@@ -40,6 +42,7 @@ import org.mapstruct.ap.testutil.runner.AnnotationProcessorTestRunner;
 @IssueKey("775")
 @WithClasses({
     MapperWithForgedIterableMapping.class,
+    MapperWithCustomListMapping.class,
     ListContainer.class,
     IterableContainer.class
 })
@@ -54,4 +57,14 @@ public class IterableWithBoundedElementTypeTest {
 
         assertThat( result.getValues() ).contains( Integer.valueOf( 42 ), Integer.valueOf( 47 ) );
     }
+
+    @Test
+    public void usesListIntegerMethodForIterableLowerBoundInteger() {
+        ListContainer source = new ListContainer();
+
+        source.setValues( Arrays.asList( "42", "47" ) );
+        IterableContainer result = MapperWithCustomListMapping.INSTANCE.toContainerWithIterable( source );
+
+        assertThat( result.getValues() ).contains( Integer.valueOf( 66 ), Integer.valueOf( 71 ) );
+    }
 }

processor/src/test/java/org/mapstruct/ap/test/bugs/_775/MapperWithForgedIterableMapping.java

@@ -0,0 +1,34 @@
+/**
+ *  Copyright 2012-2016 Gunnar Morling (http://www.gunnarmorling.de/)
+ *  and/or other contributors as indicated by the @authors tag. See the
+ *  copyright.txt file in the distribution for a full listing of all
+ *  contributors.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+package org.mapstruct.ap.test.bugs._775;
+
+import org.mapstruct.Mapper;
+import org.mapstruct.factory.Mappers;
+
+/**
+ * @author Andreas Gudian
+ */
+@Mapper
+public abstract class MapperWithForgedIterableMapping {
+    public static final MapperWithForgedIterableMapping INSTANCE =
+        Mappers.getMapper( MapperWithForgedIterableMapping.class );
+
+    public abstract IterableContainer toContainerWithIterable(ListContainer source);
+
+}