fix(44465): remove only unused declarations instead of the entire line (#44490)

Author: a-tarasyuk

src/services/textChanges.ts

@@ -174,7 +174,9 @@ namespace ts.textChanges {
             return node.getStart(sourceFile);
         }
         if (leadingTriviaOption === LeadingTriviaOption.StartLine) {
-            return getLineStartPositionForPosition(node.getStart(sourceFile), sourceFile);
+            const startPos = node.getStart(sourceFile);
+            const pos = getLineStartPositionForPosition(startPos, sourceFile);
+            return rangeContainsPosition(node, pos) ? pos : startPos;
         }
         if (leadingTriviaOption === LeadingTriviaOption.JSDoc) {
             const JSDocComments = getJSDocCommentRanges(node, sourceFile.text);

tests/cases/fourslash/codeFixUnusedIdentifier_singleLineStatements1.ts

@@ -0,0 +1,10 @@
+/// <reference path='fourslash.ts' />
+
+// @noUnusedLocals: true
+// @noUnusedParameters: true
+////export const a = 1; const b = 1;
+
+verify.codeFix({
+    description: "Remove unused declaration for: 'b'",
+    newFileContent: "export const a = 1; "
+});

tests/cases/fourslash/codeFixUnusedIdentifier_singleLineStatements2.ts

@@ -0,0 +1,11 @@
+/// <reference path='fourslash.ts' />
+
+// @noUnusedLocals: true
+// @noUnusedParameters: true
+////export function f1() {} function f2() {}
+
+verify.codeFix({
+    description: "Remove unused declaration for: 'f2'",
+    index: 0,
+    newFileContent: "export function f1() {} "
+});

tests/cases/fourslash/codeFixUnusedIdentifier_singleLineStatements3.ts

@@ -0,0 +1,11 @@
+/// <reference path='fourslash.ts' />
+
+// @noUnusedLocals: true
+// @noUnusedParameters: true
+////export class c1 {} class c2 {}
+
+verify.codeFix({
+    description: "Remove unused declaration for: 'c2'",
+    index: 0,
+    newFileContent: "export class c1 {} "
+});