#2177 Mapping into a generic class / record with a typed constructor argument should work

integrationtest/src/test/resources/recordsTest/src/main/java/org/mapstruct/itest/records/CustomerMapper.java

@@ -24,4 +24,7 @@ public interface CustomerMapper {
     @InheritInverseConfiguration
     CustomerDto toRecord(CustomerEntity entity);
 
+    @Mapping(target = "value", source = "name")
+    GenericRecord<String> toValue(CustomerEntity entity);
+
 }

integrationtest/src/test/resources/recordsTest/src/main/java/org/mapstruct/itest/records/GenericRecord.java

@@ -0,0 +1,13 @@
+/*
+ * Copyright MapStruct Authors.
+ *
+ * Licensed under the Apache License version 2.0, available at http://www.apache.org/licenses/LICENSE-2.0
+ */
+package org.mapstruct.itest.records;
+
+/**
+ * @author Filip Hrisafov
+ */
+public record GenericRecord<T>(T value) {
+
+}

integrationtest/src/test/resources/recordsTest/src/test/java/org/mapstruct/itest/records/RecordsTest.java

@@ -35,4 +35,16 @@ public class RecordsTest {
         assertThat( customer.name() ).isEqualTo( "Kermit" );
         assertThat( customer.email() ).isEqualTo( "kermit@test.com" );
     }
+
+    @Test
+    public void shouldMapIntoGenericRecord() {
+        CustomerEntity entity = new CustomerEntity();
+        entity.setName( "Kermit" );
+        entity.setMail( "kermit@test.com" );
+
+        GenericRecord<String> value = CustomerMapper.INSTANCE.toValue( entity );
+
+        assertThat( value ).isNotNull();
+        assertThat( value.value() ).isEqualTo( "Kermit" );
+    }
 }

processor/src/main/java/org/mapstruct/ap/internal/model/BeanMappingMethod.java

@@ -27,6 +27,7 @@ import javax.lang.model.element.Element;
 import javax.lang.model.element.ExecutableElement;
 import javax.lang.model.element.Modifier;
 import javax.lang.model.type.DeclaredType;
+import javax.lang.model.type.TypeMirror;
 import javax.lang.model.util.ElementFilter;
 import javax.tools.Diagnostic;
 
@@ -598,15 +599,21 @@ public class BeanMappingMethod extends NormalTypeMappingMethod {
                 List<ParameterBinding> parameterBindings = new ArrayList<>( recordComponents.size() );
                 Map<String, Accessor> constructorAccessors = new LinkedHashMap<>();
                 for ( Element recordComponent : recordComponents ) {
+                    TypeMirror recordComponentMirror = ctx.getTypeUtils()
+                        .asMemberOf( (DeclaredType) type.getTypeMirror(), recordComponent );
                     String parameterName = recordComponent.getSimpleName().toString();
-                    Accessor accessor = createConstructorAccessor( recordComponent, parameterName );
+                    Accessor accessor = createConstructorAccessor(
+                        recordComponent,
+                        recordComponentMirror,
+                        parameterName
+                    );
                     constructorAccessors.put(
                         parameterName,
                         accessor
                     );
 
                     parameterBindings.add( ParameterBinding.fromTypeAndName(
-                        ctx.getTypeFactory().getType( recordComponent.asType() ),
+                        ctx.getTypeFactory().getType( recordComponentMirror ),
                         accessor.getSimpleName()
                     ) );
                 }
@@ -718,7 +725,11 @@ public class BeanMappingMethod extends NormalTypeMappingMethod {
                 for ( Parameter constructorParameter : constructorParameters ) {
                     String parameterName = constructorParameter.getName();
                     Element parameterElement = constructorParameter.getElement();
-                    Accessor constructorAccessor = createConstructorAccessor( parameterElement, parameterName );
+                    Accessor constructorAccessor = createConstructorAccessor(
+                        parameterElement,
+                        constructorParameter.getType().getTypeMirror(),
+                        parameterName
+                    );
                     constructorAccessors.put(
                         parameterName,
                         constructorAccessor
@@ -746,7 +757,11 @@ public class BeanMappingMethod extends NormalTypeMappingMethod {
                     String parameterName = constructorProperties.get( i );
                     Parameter constructorParameter = constructorParameters.get( i );
                     Element parameterElement = constructorParameter.getElement();
-                    Accessor constructorAccessor = createConstructorAccessor( parameterElement, parameterName );
+                    Accessor constructorAccessor = createConstructorAccessor(
+                        parameterElement,
+                        constructorParameter.getType().getTypeMirror(),
+                        parameterName
+                    );
                     constructorAccessors.put(
                         parameterName,
                         constructorAccessor
@@ -761,13 +776,13 @@ public class BeanMappingMethod extends NormalTypeMappingMethod {
             }
         }
 
-        private Accessor createConstructorAccessor(Element element, String parameterName) {
+        private Accessor createConstructorAccessor(Element element, TypeMirror accessedType, String parameterName) {
             String safeParameterName = Strings.getSafeVariableName(
                 parameterName,
                 existingVariableNames
             );
             existingVariableNames.add( safeParameterName );
-            return new ParameterElementAccessor( element, safeParameterName );
+            return new ParameterElementAccessor( element, accessedType, safeParameterName );
         }
 
         private boolean hasDefaultAnnotationFromAnyPackage(Element element) {

processor/src/main/java/org/mapstruct/ap/internal/util/accessor/ParameterElementAccessor.java

@@ -17,10 +17,12 @@ import javax.lang.model.type.TypeMirror;
 public class ParameterElementAccessor extends AbstractAccessor<Element> {
 
     protected final String name;
+    protected final TypeMirror accessedType;
 
-    public ParameterElementAccessor(Element element, String name) {
+    public ParameterElementAccessor(Element element, TypeMirror accessedType, String name) {
         super( element );
         this.name = name;
+        this.accessedType = accessedType;
     }
 
     @Override
@@ -30,7 +32,7 @@ public class ParameterElementAccessor extends AbstractAccessor<Element> {
 
     @Override
     public TypeMirror getAccessedType() {
-        return element.asType();
+        return accessedType;
     }
 
     @Override

processor/src/test/java/org/mapstruct/ap/test/bugs/_2177/Issue2177Mapper.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright MapStruct Authors.
+ *
+ * Licensed under the Apache License version 2.0, available at http://www.apache.org/licenses/LICENSE-2.0
+ */
+package org.mapstruct.ap.test.bugs._2177;
+
+import org.mapstruct.Mapper;
+import org.mapstruct.factory.Mappers;
+
+/**
+ * @author Filip Hrisafov
+ */
+@Mapper
+public interface Issue2177Mapper {
+
+    Issue2177Mapper INSTANCE = Mappers.getMapper( Issue2177Mapper.class );
+
+    Target<String> map(Source source);
+
+    class Source {
+        private final String value;
+
+        public Source(String value) {
+            this.value = value;
+        }
+
+        public String getValue() {
+            return value;
+        }
+    }
+
+    class Target<T> {
+        private final T value;
+
+        public Target(T value) {
+            this.value = value;
+        }
+
+        public T getValue() {
+            return value;
+        }
+    }
+}

processor/src/test/java/org/mapstruct/ap/test/bugs/_2177/Issue2177Test.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright MapStruct Authors.
+ *
+ * Licensed under the Apache License version 2.0, available at http://www.apache.org/licenses/LICENSE-2.0
+ */
+package org.mapstruct.ap.test.bugs._2177;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mapstruct.ap.testutil.IssueKey;
+import org.mapstruct.ap.testutil.WithClasses;
+import org.mapstruct.ap.testutil.runner.AnnotationProcessorTestRunner;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * @author Filip Hrisafov
+ */
+@IssueKey("2177")
+@RunWith(AnnotationProcessorTestRunner.class)
+@WithClasses({
+    Issue2177Mapper.class
+})
+public class Issue2177Test {
+
+    @Test
+    public void shouldCorrectlyUseGenericClassesWithConstructorMapping() {
+
+        Issue2177Mapper.Target<String> target = Issue2177Mapper.INSTANCE.map( new Issue2177Mapper.Source( "test" ) );
+
+        assertThat( target ).isNotNull();
+        assertThat( target.getValue() ).isEqualTo( "test" );
+    }
+}