fix(50654): "Move to a new file" breaks the declaration of referenced variable

src/services/refactors/moveToNewFile.ts

@@ -402,7 +402,13 @@ namespace ts.refactor {
         switch (name.kind) {
             case SyntaxKind.Identifier:
                 if (isUnused(name)) {
-                    changes.delete(sourceFile, name);
+                    if (varDecl.initializer && isRequireCall(varDecl.initializer, /*requireStringLiteralLikeArgument*/ true)) {
+                        changes.delete(sourceFile,
+                            isVariableDeclarationList(varDecl.parent) && length(varDecl.parent.declarations) === 1 ? varDecl.parent.parent : varDecl);
+                    }
+                    else {
+                        changes.delete(sourceFile, name);
+                    }
                 }
                 break;
             case SyntaxKind.ArrayBindingPattern:

tests/cases/fourslash/moveToNewFile_requireImport1.ts

@@ -0,0 +1,28 @@
+/// <reference path="fourslash.ts" />
+
+// @allowJs: true
+
+// @filename: /a.js
+////module.exports = 1;
+
+// @filename: /b.js
+////var a = require("./a");
+////[|function f() {
+////    a;
+////}|]
+
+verify.noErrors();
+
+verify.moveToNewFile({
+    newFileContents: {
+        "/b.js": "",
+
+        "/f.js":
+`var a = require("./a");
+
+function f() {
+    a;
+}
+`,
+    },
+});

tests/cases/fourslash/moveToNewFile_requireImport2.ts

@@ -0,0 +1,33 @@
+/// <reference path="fourslash.ts" />
+
+// @allowJs: true
+
+// @filename: /a.js
+////module.exports = 1;
+
+// @filename: /b.js
+////var a = require("./a"),
+////    b = require("./a"),
+////    c = require("./a");
+////[|function f() {
+////    b;
+////}|]
+
+verify.noErrors();
+
+verify.moveToNewFile({
+    newFileContents: {
+        "/b.js":
+`var a = require("./a"),
+    c = require("./a");
+`,
+
+        "/f.js":
+`var b = require("./a");
+
+function f() {
+    b;
+}
+`,
+    },
+});