ground type for explicitly typed lambda: add sam to target class substitution (IDEA-166662)

java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/FunctionalInterfaceParameterizationUtil.java

@@ -18,6 +18,7 @@ package com.intellij.psi.impl.source.resolve.graphInference;
 import com.intellij.openapi.diagnostic.Logger;
 import com.intellij.psi.*;
 import com.intellij.psi.impl.source.resolve.graphInference.constraints.TypeEqualityConstraint;
+import com.intellij.psi.util.TypeConversionUtil;
 import com.intellij.util.containers.ContainerUtil;
 import org.jetbrains.annotations.Nullable;
 
@@ -92,6 +93,8 @@ public class FunctionalInterfaceParameterizationUtil {
 
       final PsiMethod interfaceMethod = LambdaUtil.getFunctionalInterfaceMethod(resolveResult);
       if (interfaceMethod == null) return null;
+      final PsiClass samClass = interfaceMethod.getContainingClass();
+      if (samClass == null) return null;
 
       PsiTypeParameter[] typeParameters = psiClass.getTypeParameters();
       if (typeParameters.length != parameters.length) {
@@ -103,11 +106,13 @@ public class FunctionalInterfaceParameterizationUtil {
         return null;
       }
 
+      final PsiSubstitutor lambdaSubstitutor = TypeConversionUtil.getSuperClassSubstitutor(samClass, psiClass, PsiSubstitutor.EMPTY);
+
       final InferenceSession session = new InferenceSession(typeParameters, PsiSubstitutor.EMPTY, expr.getManager(), expr);
 
       for (int i = 0; i < targetMethodParams.length; i++) {
-        session.addConstraint(new TypeEqualityConstraint(lambdaParams[i].getType(),
-                                                         session.substituteWithInferenceVariables(targetMethodParams[i].getType())));
+        final PsiType qType = lambdaSubstitutor.substitute(targetMethodParams[i].getType());
+        session.addConstraint(new TypeEqualityConstraint(lambdaParams[i].getType(), session.substituteWithInferenceVariables(qType)));
       }
 
       if (!session.repeatInferencePhases()) {

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/newLambda/GroundTargetTypeWhenAbstractMethodInSuperclass.java

@@ -0,0 +1,13 @@
+import java.util.function.Consumer;
+
+class Main {
+
+  private static void test() {
+    extendsConsumer((String s) -> {});
+  }
+
+  private static <T> void extendsConsumer(ExtendsConsumer<? super T> c) { }
+
+  interface ExtendsConsumer<T> extends Consumer<T> { }
+
+}

java/java-tests/testSrc/com/intellij/codeInsight/daemon/lambda/NewLambdaHighlightingTest.java

@@ -339,6 +339,10 @@ public class NewLambdaHighlightingTest extends LightDaemonAnalyzerTestCase {
     doTest();
   }
 
+  public void testGroundTargetTypeWhenAbstractMethodInSuperclass() throws Exception {
+    doTest();
+  }
+
   private void doTest() {
     IdeaTestUtil.setTestVersion(JavaSdkVersion.JDK_1_8, getModule(), getTestRootDisposable());
     doTest(BASE_PATH + "/" + getTestName(false) + ".java", false, false);