Iterate Intention: Fix detection of extension iterators

#KT-8616 Fixed

idea/idea-completion/testData/handlers/smart/ForLoopRange.kt

@@ -1,9 +1,9 @@
 interface X
 interface Y
 
-fun X.iterator(): Y
-fun Y.next(): Int
-fun Y.hasNext(): Boolean
+operator fun X.iterator(): Y
+operator fun Y.next(): Int
+operator fun Y.hasNext(): Boolean
 
 
 fun foo(x: X) {

idea/idea-completion/testData/handlers/smart/ForLoopRange.kt.after

@@ -1,9 +1,9 @@
 interface X
 interface Y
 
-fun X.iterator(): Y
-fun Y.next(): Int
-fun Y.hasNext(): Boolean
+operator fun X.iterator(): Y
+operator fun Y.next(): Int
+operator fun Y.hasNext(): Boolean
 
 
 fun foo(x: X) {

idea/idea-completion/testData/handlers/smart/ForLoopRange2.kt

@@ -1,9 +1,9 @@
 interface X
 interface Y
 
-fun X.iterator(): Y
-fun Y.next(): Int
-fun Y.hasNext(): Boolean
+operator fun X.iterator(): Y
+operator fun Y.next(): Int
+operator fun Y.hasNext(): Boolean
 
 
 fun foo(x: X?) {

idea/idea-completion/testData/handlers/smart/ForLoopRange2.kt.after

@@ -1,9 +1,9 @@
 interface X
 interface Y
 
-fun X.iterator(): Y
-fun Y.next(): Int
-fun Y.hasNext(): Boolean
+operator fun X.iterator(): Y
+operator fun Y.next(): Int
+operator fun Y.hasNext(): Boolean
 
 
 fun foo(x: X?) {

idea/idea-completion/testData/smart/forLoopRange/ExtensionIteratorMethod.kt

@@ -1,9 +1,9 @@
 interface X
 interface Y
 
-fun X.iterator(): Y
-fun Y.next(): Int
-fun Y.hasNext(): Boolean
+operator fun X.iterator(): Y
+operator fun Y.next(): Int
+operator fun Y.hasNext(): Boolean
 
 
 fun foo(x: X, y: Y) {

idea/idea-core/src/org/jetbrains/kotlin/idea/core/IterableTypesDetection.kt

@@ -17,6 +17,7 @@
 package org.jetbrains.kotlin.idea.core
 
 import com.intellij.openapi.project.Project
+import org.jetbrains.kotlin.descriptors.TypeParameterDescriptor
 import org.jetbrains.kotlin.idea.util.FuzzyType
 import org.jetbrains.kotlin.incremental.components.NoLookupLocation
 import org.jetbrains.kotlin.name.Name
@@ -79,7 +80,10 @@ public class IterableTypesDetection(
 
         private fun canBeIterable(type: FuzzyType): Boolean {
             return type.type.memberScope.getContributedFunctions(iteratorName, NoLookupLocation.FROM_IDE).isNotEmpty() ||
-                   typesWithExtensionIterator.any { type.checkIsSubtypeOf(it) != null }
+                   typesWithExtensionIterator.any {
+                       val freeParams = it.arguments.mapNotNull { it.type.constructor.declarationDescriptor as? TypeParameterDescriptor }
+                       type.checkIsSubtypeOf(FuzzyType(it, freeParams)) != null
+                   }
         }
     }
 }

idea/testData/intentions/iterateExpression/extensionIterator.kt

@@ -0,0 +1,8 @@
+// WITH_RUNTIME
+class T<U>
+
+operator fun <U> T<U>.iterator(): Iterator<U> = listOf<U>().iterator()
+
+fun test() {
+    T<Int>()<caret>
+}

idea/testData/intentions/iterateExpression/extensionIterator.kt.after

@@ -0,0 +1,10 @@
+// WITH_RUNTIME
+class T<U>
+
+operator fun <U> T<U>.iterator(): Iterator<U> = listOf<U>().iterator()
+
+fun test() {
+    for (i in T<Int>()) {
+        <caret>
+    }
+}

idea/testData/intentions/iterateExpression/extensionIteratorWithPartialSubstitution1.kt

@@ -0,0 +1,8 @@
+// WITH_RUNTIME
+class T<U, V>
+
+operator fun <X> T<X, String>.iterator(): Iterator<X> = listOf<X>().iterator()
+
+fun test() {
+    T<Int, String>()<caret>
+}

idea/testData/intentions/iterateExpression/extensionIteratorWithPartialSubstitution1.kt.after

@@ -0,0 +1,10 @@
+// WITH_RUNTIME
+class T<U, V>
+
+operator fun <X> T<X, String>.iterator(): Iterator<X> = listOf<X>().iterator()
+
+fun test() {
+    for (i in T<Int, String>()) {
+        <caret>
+    }
+}

idea/testData/intentions/iterateExpression/extensionIteratorWithPartialSubstitution2.kt

@@ -0,0 +1,9 @@
+// WITH_RUNTIME
+// IS_APPLICABLE: false
+class T<U, V>
+
+operator fun <X> T<X, String>.iterator(): Iterator<X> = listOf<X>().iterator()
+
+fun test() {
+    T<Int, Boolean>()<caret>
+}

idea/testData/intentions/iterateExpression/mapIterator.kt

@@ -0,0 +1,4 @@
+// WITH_RUNTIME
+fun test() {
+    mapOf(1 to "1", 2 to "2")<caret>
+}

idea/testData/intentions/iterateExpression/mapIterator.kt.after

@@ -0,0 +1,6 @@
+// WITH_RUNTIME
+fun test() {
+    for (entry in mapOf(1 to "1", 2 to "2")) {
+        <caret>
+    }
+}

idea/tests/org/jetbrains/kotlin/idea/intentions/IntentionTestGenerated.java

@@ -5817,12 +5817,36 @@ public class IntentionTestGenerated extends AbstractIntentionTest {
             KotlinTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("idea/testData/intentions/iterateExpression"), Pattern.compile("^([\\w\\-_]+)\\.kt$"), true);
         }
 
+        @TestMetadata("extensionIterator.kt")
+        public void testExtensionIterator() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/iterateExpression/extensionIterator.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("extensionIteratorWithPartialSubstitution1.kt")
+        public void testExtensionIteratorWithPartialSubstitution1() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/iterateExpression/extensionIteratorWithPartialSubstitution1.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("extensionIteratorWithPartialSubstitution2.kt")
+        public void testExtensionIteratorWithPartialSubstitution2() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/iterateExpression/extensionIteratorWithPartialSubstitution2.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("functionCall.kt")
         public void testFunctionCall() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/iterateExpression/functionCall.kt");
             doTest(fileName);
         }
 
+        @TestMetadata("mapIterator.kt")
+        public void testMapIterator() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/iterateExpression/mapIterator.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("nameSuggestion.kt")
         public void testNameSuggestion() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/iterateExpression/nameSuggestion.kt");