Don't delete comments when deleting unused declarations (#37467)

* don't delete comment on variable declaration

* add more declaration kinds

* don't copy comment in convertes6 class

* don't copy comments in convertToES6Class

* add tests

* use isAnyImportSyntax

* handle mixed comment types

* update tests

tests/cases/fourslash/server/convertFunctionToEs6Class-server1.ts

@@ -14,7 +14,7 @@
 verify.codeFix({
     description: "Convert function to an ES2015 class",
     newFileContent:
-`// Comment\r
+`// Comment
 class fn {\r
     constructor() {\r
         this.baz = 10;\r

tests/cases/fourslash/server/convertFunctionToEs6Class-server2.ts

@@ -0,0 +1,31 @@
+// @allowNonTsExtensions: true
+// @Filename: test123.js
+
+/// <reference path="../fourslash.ts" />
+
+//// /**
+////  * JSDoc Comment
+////  */
+//// function fn() {
+////     this.baz = 10;
+//// }
+//// /*1*/fn.prototype.bar = function () {
+////     console.log('hello world');
+//// }
+
+verify.codeFix({
+    description: "Convert function to an ES2015 class",
+    newFileContent:
+`/**\r
+ * JSDoc Comment\r
+ */\r
+class fn {\r
+    constructor() {\r
+        this.baz = 10;\r
+    }\r
+    bar() {\r
+        console.log('hello world');\r
+    }\r
+}\r
+`,
+});

tests/cases/fourslash/unusedClassInNamespaceWithTrivia1.ts

@@ -8,4 +8,5 @@
 //// } |]
 
 verify.rangeAfterCodeFix(`namespace greeter {
+   /* comment1 */
 }`);

tests/cases/fourslash/unusedClassInNamespaceWithTrivia2.ts

@@ -0,0 +1,16 @@
+/// <reference path='fourslash.ts' />
+
+// @noUnusedLocals: true
+//// [| namespace greeter {
+////   // Do not remove
+////   /**
+////    * JSDoc Comment
+////    */
+////   class /* comment2 */ class1 {
+////   }
+//// } |]
+
+verify.rangeAfterCodeFix(`namespace greeter {
+   // Do not remove
+}`);
+ 

tests/cases/fourslash/unusedFunctionInNamespace1.ts

@@ -8,4 +8,5 @@
 //// } |]
 
 verify.rangeAfterCodeFix(`namespace greeter {
+   // some legit comments
 }`);

tests/cases/fourslash/unusedFunctionInNamespaceWithTrivia.ts

@@ -0,0 +1,16 @@
+/// <reference path='fourslash.ts' />
+
+// @noUnusedLocals: true
+//// [| namespace greeter {
+////   // Do not remove
+////   /**
+////    * JSDoc Comment
+////    */
+////   function function1() {
+////   }/*1*/
+//// } |]
+
+verify.rangeAfterCodeFix(`namespace greeter {
+    // Do not remove
+ }`);
+ 

tests/cases/fourslash/unusedVariableWithTrivia1.ts

@@ -0,0 +1,20 @@
+/// <reference path='fourslash.ts' />
+
+// @noUnusedLocals: true
+////[|namespace greeter {
+////    // do not remove comment
+////    let a = 0;
+////    // comment
+////    let b = 0;
+////    b;
+////}|]
+
+verify.codeFix({
+    description: "Remove unused declaration for: 'a'",
+    newRangeContent: `namespace greeter {
+    // do not remove comment
+    // comment
+    let b = 0;
+    b;
+}`
+});

tests/cases/fourslash/unusedVariableWithTrivia2.ts

@@ -0,0 +1,17 @@
+/// <reference path='fourslash.ts' />
+
+// @noUnusedLocals: true
+////[|namespace greeter {
+////    // Do not remove
+////    /**
+////     * JSDoc Comment
+////     */
+////    let a = 0;
+////}|]
+
+verify.codeFix({
+    description: "Remove unused declaration for: 'a'",
+    newRangeContent: `namespace greeter {
+    // Do not remove
+}`
+});