fix type parameter migration for extension functions

idea/src/org/jetbrains/kotlin/idea/formatter/kotlinSpacingRules.kt

@@ -141,6 +141,7 @@ fun createSpacingBuilder(settings: CodeStyleSettings): KotlinSpacingBuilder {
 
             betweenInside(FUN_KEYWORD, IDENTIFIER, FUN).spaces(1)
             betweenInside(FUN_KEYWORD, TYPE_REFERENCE, FUN).spaces(1)
+            betweenInside(TYPE_PARAMETER_LIST, TYPE_REFERENCE, FUN).spaces(1)
             betweenInside(TYPE_PARAMETER_LIST, IDENTIFIER, FUN).spaces(1)
             betweenInside(FUN_KEYWORD, VALUE_PARAMETER_LIST, FUN).spacing(0, 0, 0, false, 0)
             betweenInside(TYPE_REFERENCE, DOT, FUN).spacing(0, 0, 0, false, 0)

idea/src/org/jetbrains/kotlin/idea/quickfix/migration/MigrateTypeParameterListFix.kt

@@ -36,7 +36,7 @@ class MigrateTypeParameterListFix(typeParameterList: JetTypeParameterList)
 
     override fun invoke(project: Project, editor: Editor?, file: JetFile) {
         val function = element.getStrictParentOfType<JetNamedFunction>() ?: return
-        function.addBefore(element, function.nameIdentifier)
+        function.addBefore(element, function.receiverTypeReference ?: function.nameIdentifier)
         element.delete()
     }
 

idea/testData/quickfix/migration/typeParameterList/extension.kt

@@ -0,0 +1,5 @@
+// "Migrate type parameter list syntax" "true"
+
+class Foo
+
+fun Foo.f<caret><T>() {}

idea/testData/quickfix/migration/typeParameterList/extension.kt.after

@@ -0,0 +1,5 @@
+// "Migrate type parameter list syntax" "true"
+
+class Foo
+
+fun <T> Foo.f() {}

idea/tests/org/jetbrains/kotlin/idea/quickfix/QuickFixTestGenerated.java

@@ -4356,6 +4356,12 @@ public class QuickFixTestGenerated extends AbstractQuickFixTest {
                 String fileName = JetTestUtils.navigationMetadata("idea/testData/quickfix/migration/typeParameterList/basic.kt");
                 doTest(fileName);
             }
+
+            @TestMetadata("extension.kt")
+            public void testExtension() throws Exception {
+                String fileName = JetTestUtils.navigationMetadata("idea/testData/quickfix/migration/typeParameterList/extension.kt");
+                doTest(fileName);
+            }
         }
     }