Fixed language injection when target is field

Fixes #95

Author: Cerber-Ursi

change-notes.html

@@ -3,6 +3,7 @@ <h2>1.4.0</h2>
 <ul>
     <li>Suppress redundant default parameter value assignment warning for <code>Mapping#constant</code> and <code>Mapping#defaultValue</code></li>
     <li>Support for Java records</li>
+    <li>Bug fix: language injections inside expressions when target is field</li>
 </ul>
 <h2>1.3.1</h2>
 <ul>

src/main/java/org/mapstruct/intellij/expression/JavaExpressionInjector.java

@@ -27,6 +27,7 @@
 import com.intellij.psi.PsiClassObjectAccessExpression;
 import com.intellij.psi.PsiClassType;
 import com.intellij.psi.PsiElement;
+import com.intellij.psi.PsiField;
 import com.intellij.psi.PsiJavaCodeReferenceElement;
 import com.intellij.psi.PsiLanguageInjectionHost;
 import com.intellij.psi.PsiLiteralExpression;
@@ -181,6 +182,9 @@ public void getLanguagesToInject(@NotNull MultiHostRegistrar registrar, @NotNull
                             else if ( resolved instanceof PsiParameter ) {
                                 targetType = ( (PsiParameter) resolved ).getType();
                             }
+                            else if ( resolved instanceof PsiField) {
+                                targetType = ( (PsiField) resolved ).getType();
+                            }
                         }
                     }
                     break;

src/test/java/org/mapstruct/intellij/expression/JavaExpressionInjectionTest.java

@@ -160,6 +160,23 @@ public class JavaExpressionInjectionTest extends MapstructBaseCompletionTestCase
         "    CarDto carToCarDto(Car car, String make);\n" +
         "}";
 
+    @Language("java")
+    private static final String MAPPER_TO_DTO_WITHOUT_ACCESSORS = "" +
+        "import java.util.List;\n" +
+        "\n" +
+        "import org.mapstruct.Mapper;\n" +
+        "import org.mapstruct.Mapping;\n" +
+        "import org.mapstruct.Mappings;\n" +
+        "import org.example.dto.CarPlainDto;\n" +
+        "import org.example.dto.Car;\n" +
+        "\n" +
+        "@Mapper(" + MAPPER + ")\n" +
+        "public interface CarMapper {\n" +
+        "\n" +
+        "    " + MAPPING + "\n" +
+        "    CarPlainDto carToCarPlainDto(Car car);\n" +
+        "}";
+
     @Override
     protected String getTestDataPath() {
         return "testData/expression";
@@ -602,6 +619,41 @@ protected void withTargetUsingStaticString(String attribute) {
             "}" );
     }
 
+    public void testExpressionWithMapperToDtoWithoutAccessors() {
+        withMapperToDtoWithoutAccessors( "expression" );
+        withMapperToDtoWithoutAccessors( "defaultExpression" );
+    }
+
+    protected void withMapperToDtoWithoutAccessors(String attribute) {
+        String mapping = "@Mapping(target = \"manufacturingYear\", " + attribute + " = \"java(car.<caret>)\")\n";
+        @Language("java")
+        String mapper = formatMapper( MAPPER_TO_DTO_WITHOUT_ACCESSORS, mapping );
+        PsiFile file = configureMapperByText( mapper );
+
+        assertThat( myFixture.completeBasic() )
+            .extracting( LookupElementPresentation::renderElement )
+            .extracting( LookupElementPresentation::getItemText )
+            .contains(
+                "getMake",
+                "setMake",
+                "getManufacturingDate",
+                "setManufacturingDate",
+                "getNumberOfSeats",
+                "setNumberOfSeats"
+            );
+
+        assertThat( myFixture.complete( CompletionType.SMART ) )
+            .extracting( LookupElementPresentation::renderElement )
+            .extracting( LookupElementPresentation::getItemText )
+            .containsExactlyInAnyOrder( "getMake", "toString" );
+
+        PsiElement elementAt = file.findElementAt( myFixture.getCaretOffset() );
+        assertThat( elementAt )
+            .isNotNull()
+            .isInstanceOf( PsiJavaToken.class );
+        assertThat( elementAt.getText() ).isEqualTo( ";" );
+    }
+
     private PsiFile configureMapperByText(@Language("java") String text) {
         return myFixture.configureByText( JavaFileType.INSTANCE, text );
     }

testData/expression/dto/CarPlainDto.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.example.dto;
+
+public class CarPlainDto {
+
+    public String make;
+    public int seatCount;
+    public String manufacturingYear;
+}