type migration: fix AIOOBE for method with generic varargs migration (EA-87127)

java/java-impl/src/com/intellij/refactoring/typeMigration/rules/RootTypeConversionRule.java

@@ -118,8 +118,7 @@ public class RootTypeConversionRule extends TypeConversionRule {
                   }
 
                   final PsiType migrationType = methodTypeParamsSubstitutor.substitute(type);
-                  if (!originalType.equals(migrationType) &&
-                      !TypeConversionUtil.areTypesAssignmentCompatible(migrationType, actualParams[i])) {
+                  if (!originalType.equals(migrationType) && !areParametersAssignable(migrationType, i, actualParams)) {
                     labeler.migrateExpressionType(actualParams[i], migrationType, context, false, true);
                   }
                 }
@@ -139,6 +138,19 @@ public class RootTypeConversionRule extends TypeConversionRule {
     return null;
   }
 
+  private static boolean areParametersAssignable(PsiType migrationType, int paramId, PsiExpression[] actualParams) {
+    if (migrationType instanceof PsiEllipsisType) {
+      for (int i = paramId; i < actualParams.length; i++) {
+        if (!TypeConversionUtil.areTypesAssignmentCompatible(migrationType, actualParams[i])) {
+          return false;
+        }
+      }
+      return true;
+    } else {
+      return TypeConversionUtil.areTypesAssignmentCompatible(migrationType, actualParams[paramId]);
+    }
+  }
+
   private static class MyStaticMethodConversionDescriptor extends TypeConversionDescriptorBase {
     private final @NotNull String myTargetClassQName;
 

java/typeMigration/test/com/intellij/refactoring/TypeMigrationTest.java

@@ -862,6 +862,10 @@ public class TypeMigrationTest extends TypeMigrationTestBase {
     doTestMethodType("migrationMethod", PsiType.VOID);
   }
 
+  public void testGenericEllipsis() {
+    doTestFieldType("migrationField", myJavaFacade.getElementFactory().createTypeFromText("Test<Short>", null));
+  }
+
   private void doTestReturnType(final String methodName, final String migrationType) {
     start(new RulesProvider() {
       @Override

java/typeMigration/testData/refactoring/typeMigration/genericEllipsis/after/Test.items

@@ -0,0 +1,10 @@
+Types:
+PsiField:migrationField : Test<java.lang.Short>
+PsiMethodCallExpression:migrationField.method() : void
+PsiReferenceExpression:migrationField : Test<java.lang.Short>
+
+Conversions:
+migrationField.method() -> $
+
+New expression type changes:
+Fails:

java/typeMigration/testData/refactoring/typeMigration/genericEllipsis/after/test.java

@@ -0,0 +1,11 @@
+class Test<X> {
+    private static Test<Short> migrationField;
+
+    private static void m() {
+        migrationField.method();
+    }
+
+    void method(X... xes) {
+
+    }
+}

java/typeMigration/testData/refactoring/typeMigration/genericEllipsis/before/test.java

@@ -0,0 +1,11 @@
+class Test<X> {
+    private static Test<Integer> migrationField;
+
+    private static void m() {
+        migrationField.method();
+    }
+
+    void method(X... xes) {
+
+    }
+}