java method reference inference: keep additional inference variables when second search is not possible (IDEA-252839)

GitOrigin-RevId: 358b0408221aaf6e51dbf87867ae8f33ba0d0fde

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

@@ -209,7 +209,12 @@ public class PsiMethodReferenceCompatibilityConstraint implements ConstraintForm
       if (qContainingClass != null && PsiUtil.isRawSubstitutor(qContainingClass, qualifierResolveResult.getSubstitutor())) {
         //15.13.1 If there exist a parameterization, then it would be used to search, the *raw type* would be used otherwise
         if (getParameterization(signature, qualifierResolveResult, method, myExpression, qContainingClass) == null) {
-          referencedMethodReturnType = TypeConversionUtil.erasure(referencedMethodReturnType);
+          if (!PsiMethodReferenceUtil.isSecondSearchPossible(signature.getParameterTypes(), qualifierResolveResult, myExpression)) {
+            session.initBounds(myExpression, qContainingClass.getTypeParameters());
+          }
+          else {
+            referencedMethodReturnType = TypeConversionUtil.erasure(referencedMethodReturnType);
+          }
         }
       }
 

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/newMethodRef/TypeArgumentsOnFirstSearchAccessibleMethod.java

@@ -0,0 +1,16 @@
+import java.util.*;
+
+interface Foo<T> {
+  static <E> Foo<E> of(E e1) {
+    return null;
+  }
+  
+  T get(int i);
+  
+}
+class MainTest {
+  {
+    Optional.of("one,two").map(Foo::<String>of).get().get(0).split(",");
+    Optional.of("one,two").map(Foo::of).get().get(0).split(",");
+  }
+}

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

@@ -198,6 +198,7 @@ public class NewMethodRefHighlightingTest extends LightDaemonAnalyzerTestCase {
   public void testCreateMethodFromMethodRefApplicability() { doTest(); }
   public void testErrorMessageOnTopCallWhenFunctionalInterfaceIsNotInferred() { doTest(); }
   public void testReferencesToPolymorphicMethod() { doTest(); }
+  public void testTypeArgumentsOnFirstSearchAccessibleMethod() { doTest(); }
 
   private void doTest() {
     doTest(false);