#2005 Parameter type should only be checked if we are mapping from a single argument source

processor/src/main/java/org/mapstruct/ap/internal/processor/MethodRetrievalProcessor.java

@@ -512,6 +512,7 @@ public class MethodRetrievalProcessor implements ModelElementProcessor<Void, Lis
                 return false;
         }
 
+        if ( sourceParameters.size() == 1 ) {
             Type parameterType = sourceParameters.get( 0 ).getType();
 
             if ( isStreamTypeOrIterableFromJavaStdLib( parameterType ) && !resultType.isIterableOrStreamType() ) {
@@ -519,11 +520,6 @@ public class MethodRetrievalProcessor implements ModelElementProcessor<Void, Lis
                 return false;
             }
 
-        if ( containsTargetTypeParameter ) {
-            messager.printMessage( method, Message.RETRIEVAL_MAPPING_HAS_TARGET_TYPE_PARAMETER );
-            return false;
-        }
-
             if ( !parameterType.isIterableOrStreamType() && isStreamTypeOrIterableFromJavaStdLib( resultType ) ) {
                 messager.printMessage( method, Message.RETRIEVAL_NON_ITERABLE_TO_ITERABLE );
                 return false;
@@ -534,6 +530,24 @@ public class MethodRetrievalProcessor implements ModelElementProcessor<Void, Lis
                 return false;
             }
 
+            for ( Type typeParameter : parameterType.getTypeParameters() ) {
+                if ( typeParameter.hasSuperBound() ) {
+                    messager.printMessage( method, Message.RETRIEVAL_WILDCARD_SUPER_BOUND_SOURCE );
+                    return false;
+                }
+
+                if ( typeParameter.isTypeVar() ) {
+                    messager.printMessage( method, Message.RETRIEVAL_TYPE_VAR_SOURCE );
+                    return false;
+                }
+            }
+        }
+
+        if ( containsTargetTypeParameter ) {
+            messager.printMessage( method, Message.RETRIEVAL_MAPPING_HAS_TARGET_TYPE_PARAMETER );
+            return false;
+        }
+
         if ( resultType.isPrimitive() ) {
             messager.printMessage( method, Message.RETRIEVAL_PRIMITIVE_RETURN );
             return false;
@@ -550,18 +564,6 @@ public class MethodRetrievalProcessor implements ModelElementProcessor<Void, Lis
             }
         }
 
-        for ( Type typeParameter : parameterType.getTypeParameters() ) {
-            if ( typeParameter.hasSuperBound() ) {
-                messager.printMessage( method, Message.RETRIEVAL_WILDCARD_SUPER_BOUND_SOURCE );
-                return false;
-            }
-
-            if ( typeParameter.isTypeVar() ) {
-                messager.printMessage( method, Message.RETRIEVAL_TYPE_VAR_SOURCE );
-                return false;
-            }
-        }
-
         return true;
     }
 

processor/src/test/java/org/mapstruct/ap/test/multisource/MultiSourceMapper.java

@@ -0,0 +1,46 @@
+/*
+ * 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.multisource;
+
+import java.util.Collection;
+
+import org.mapstruct.Mapper;
+import org.mapstruct.ReportingPolicy;
+import org.mapstruct.factory.Mappers;
+
+/**
+ * @author Filip Hrisafov
+ */
+@Mapper(unmappedTargetPolicy = ReportingPolicy.IGNORE)
+public interface MultiSourceMapper {
+
+    MultiSourceMapper INSTANCE = Mappers.getMapper( MultiSourceMapper.class );
+
+    Target mapFromPrimitiveAndCollection(int value, Collection<String> elements);
+
+    Target mapFromCollectionAndPrimitive(Collection<String> elements, int value);
+
+    class Target {
+        private int value;
+        private Collection<String> elements;
+
+        public int getValue() {
+            return value;
+        }
+
+        public void setValue(int value) {
+            this.value = value;
+        }
+
+        public Collection<String> getElements() {
+            return elements;
+        }
+
+        public void setElements(Collection<String> elements) {
+            this.elements = elements;
+        }
+    }
+}

processor/src/test/java/org/mapstruct/ap/test/multisource/MultiSourceMapperTest.java

@@ -0,0 +1,45 @@
+/*
+ * 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.multisource;
+
+import java.util.Collections;
+
+import org.mapstruct.ap.testutil.IssueKey;
+import org.mapstruct.ap.testutil.ProcessorTest;
+import org.mapstruct.ap.testutil.WithClasses;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * @author Filip Hrisafov
+ */
+public class MultiSourceMapperTest {
+
+    @IssueKey("2005")
+    @ProcessorTest
+    @WithClasses({
+        MultiSourceMapper.class
+    })
+    void shouldBeAbleToMapFromPrimitiveAndCollectionAsMultiSource() {
+        MultiSourceMapper.Target target = MultiSourceMapper.INSTANCE.mapFromPrimitiveAndCollection(
+            10,
+            Collections.singleton( "test" )
+        );
+
+        assertThat( target ).isNotNull();
+        assertThat( target.getValue() ).isEqualTo( 10 );
+        assertThat( target.getElements() ).containsExactly( "test" );
+
+        target = MultiSourceMapper.INSTANCE.mapFromCollectionAndPrimitive(
+            Collections.singleton( "otherTest" ),
+            20
+        );
+
+        assertThat( target ).isNotNull();
+        assertThat( target.getValue() ).isEqualTo( 20 );
+        assertThat( target.getElements() ).containsExactly( "otherTest" );
+    }
+}