#3163: Strip wild card when checking for type assignability

processor/src/main/java/org/mapstruct/ap/internal/model/common/Type.java

@@ -629,11 +629,14 @@ public class Type extends ModelElement implements Comparable<Type> {
      * @return {@code true} if and only if this type is assignable to the given other type.
      */
     public boolean isAssignableTo(Type other) {
-        if ( TypeKind.WILDCARD == typeMirror.getKind() ) {
-            return typeUtils.contains( typeMirror, other.typeMirror );
+        TypeMirror otherMirror = other.typeMirror;
+        if ( otherMirror.getKind() == TypeKind.WILDCARD ) {
+            otherMirror = typeUtils.erasure( other.typeMirror );
         }
-
-        return typeUtils.isAssignable( typeMirror, other.typeMirror );
+        if ( TypeKind.WILDCARD == typeMirror.getKind() ) {
+            return typeUtils.contains( typeMirror, otherMirror );
+        }
+        return typeUtils.isAssignable( typeMirror, otherMirror );
     }
 
     /**

processor/src/test/java/org/mapstruct/ap/test/bugs/_3163/Issue3163Mapper.java

@@ -0,0 +1,22 @@
+/*
+ * 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._3163;
+
+import java.util.Optional;
+
+import org.mapstruct.Mapper;
+
+@Mapper
+public interface Issue3163Mapper {
+
+    Target map(Source value);
+
+    Target.Nested map(Source.Nested value);
+
+    default <T> Optional<T> wrapAsOptional(T value) {
+        return Optional.ofNullable( value );
+    }
+}

processor/src/test/java/org/mapstruct/ap/test/bugs/_3163/Issue3163Test.java

@@ -0,0 +1,21 @@
+/*
+ * 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._3163;
+
+import org.mapstruct.ap.testutil.ProcessorTest;
+import org.mapstruct.ap.testutil.WithClasses;
+
+@WithClasses({
+    Issue3163Mapper.class,
+    Source.class,
+    Target.class
+})
+class Issue3163Test {
+
+    @ProcessorTest
+    void shouldCompile() {
+    }
+}

processor/src/test/java/org/mapstruct/ap/test/bugs/_3163/Source.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._3163;
+
+/**
+ * @author Filip Hrisafov
+ */
+public class Source {
+
+    private final Nested nested;
+
+    public Source(Nested nested) {
+        this.nested = nested;
+    }
+
+    public Nested getNested() {
+        return nested;
+    }
+
+    public static class Nested {
+        private final String value;
+
+        public Nested(String value) {
+            this.value = value;
+        }
+
+        public String getValue() {
+            return value;
+        }
+    }
+}

processor/src/test/java/org/mapstruct/ap/test/bugs/_3163/Target.java

@@ -0,0 +1,38 @@
+/*
+ * 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._3163;
+
+import java.util.Optional;
+
+/**
+ * @author Filip Hrisafov
+ */
+public class Target {
+
+    private Nested nested;
+
+    public Optional<Nested> getNested() {
+        return Optional.ofNullable( nested );
+    }
+
+    @SuppressWarnings("OptionalUsedAsFieldOrParameterType")
+    public final void setNested(Optional<? extends Nested> nested) {
+        this.nested = nested.orElse( null );
+    }
+
+    public static class Nested {
+
+        private String value;
+
+        public String getValue() {
+            return value;
+        }
+
+        public void setValue(String value) {
+            this.value = value;
+        }
+    }
+}