Add "Remove 'lateinit'" quickfix for INAPPLICABLE_LATEINIT_MODIFIER

So #KT-24295 Fixed

idea/src/org/jetbrains/kotlin/idea/quickfix/QuickFixRegistrar.kt

@@ -493,6 +493,7 @@ class QuickFixRegistrar : QuickFixContributor {
         INAPPLICABLE_LATEINIT_MODIFIER.registerFactory(ChangeVariableMutabilityFix.LATEINIT_VAL_FACTORY)
         INAPPLICABLE_LATEINIT_MODIFIER.registerFactory(RemoveNullableFix.LATEINIT_FACTORY)
         INAPPLICABLE_LATEINIT_MODIFIER.registerFactory(RemovePartsFromPropertyFix.LateInitFactory)
+        INAPPLICABLE_LATEINIT_MODIFIER.registerFactory(RemoveModifierFix.createRemoveLateinitFactory())
 
         VARIABLE_WITH_REDUNDANT_INITIALIZER.registerFactory(RemoveRedundantInitializerFix)
 

idea/src/org/jetbrains/kotlin/idea/quickfix/RemoveModifierFix.kt

@@ -19,6 +19,7 @@ package org.jetbrains.kotlin.idea.quickfix
 import com.intellij.openapi.editor.Editor
 import com.intellij.openapi.project.Project
 import org.jetbrains.kotlin.diagnostics.Diagnostic
+import org.jetbrains.kotlin.diagnostics.Errors
 import org.jetbrains.kotlin.idea.core.quickfix.QuickFixUtil
 import org.jetbrains.kotlin.lexer.KtModifierKeywordToken
 import org.jetbrains.kotlin.lexer.KtTokens
@@ -119,5 +120,17 @@ class RemoveModifierFix(
                 }
             }
         }
+
+        fun createRemoveLateinitFactory(): KotlinSingleIntentionActionFactory {
+            return object : KotlinSingleIntentionActionFactory() {
+                override fun createAction(diagnostic: Diagnostic): KotlinQuickFixAction<KtModifierListOwner>? {
+                    val keyword = diagnostic.psiElement
+                    val modifierList = keyword.parent as? KtDeclarationModifierList ?: return null
+                    val property = modifierList.parent as? KtProperty ?: return null
+                    if (!property.hasModifier(KtTokens.LATEINIT_KEYWORD)) return null
+                    return RemoveModifierFix(property, KtTokens.LATEINIT_KEYWORD, isRedundant = false)
+                }
+            }
+        }
     }
 }

idea/testData/quickfix/redundantLateinit/simple.kt

@@ -0,0 +1,5 @@
+// "Remove 'lateinit' modifier" "true"
+
+class Test {
+    private <caret>lateinit var foo: String = ""
+}

idea/testData/quickfix/redundantLateinit/simple.kt.after

@@ -0,0 +1,5 @@
+// "Remove 'lateinit' modifier" "true"
+
+class Test {
+    private <caret>var foo: String = ""
+}

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

@@ -3140,6 +3140,19 @@ public class QuickFixMultiFileTestGenerated extends AbstractQuickFixMultiFileTes
         }
     }
 
+    @TestMetadata("idea/testData/quickfix/redundantLateinit")
+    @TestDataPath("$PROJECT_ROOT")
+    @RunWith(JUnit3RunnerWithInners.class)
+    public static class RedundantLateinit extends AbstractQuickFixMultiFileTest {
+        private void runTest(String testDataFilePath) throws Exception {
+            KotlinTestUtils.runTest(this::doTestWithExtraFile, TargetBackend.ANY, testDataFilePath);
+        }
+
+        public void testAllFilesPresentInRedundantLateinit() throws Exception {
+            KotlinTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("idea/testData/quickfix/redundantLateinit"), Pattern.compile("^(\\w+)\\.((before\\.Main\\.\\w+)|(test))$"), TargetBackend.ANY, true);
+        }
+    }
+
     @TestMetadata("idea/testData/quickfix/redundantModalityModifier")
     @TestDataPath("$PROJECT_ROOT")
     @RunWith(JUnit3RunnerWithInners.class)

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

@@ -8695,6 +8695,24 @@ public class QuickFixTestGenerated extends AbstractQuickFixTest {
         }
     }
 
+    @TestMetadata("idea/testData/quickfix/redundantLateinit")
+    @TestDataPath("$PROJECT_ROOT")
+    @RunWith(JUnit3RunnerWithInners.class)
+    public static class RedundantLateinit extends AbstractQuickFixTest {
+        private void runTest(String testDataFilePath) throws Exception {
+            KotlinTestUtils.runTest(this::doTest, TargetBackend.ANY, testDataFilePath);
+        }
+
+        public void testAllFilesPresentInRedundantLateinit() throws Exception {
+            KotlinTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("idea/testData/quickfix/redundantLateinit"), Pattern.compile("^([\\w\\-_]+)\\.kt$"), TargetBackend.ANY, true);
+        }
+
+        @TestMetadata("simple.kt")
+        public void testSimple() throws Exception {
+            runTest("idea/testData/quickfix/redundantLateinit/simple.kt");
+        }
+    }
+
     @TestMetadata("idea/testData/quickfix/redundantModalityModifier")
     @TestDataPath("$PROJECT_ROOT")
     @RunWith(JUnit3RunnerWithInners.class)