Increase size of span for unused declaration (#22388)

src/compiler/checker.ts

@@ -21614,7 +21614,7 @@ namespace ts {
             }
 
             if (!isRemovedPropertyFromObjectSpread(node.kind === SyntaxKind.Identifier ? node.parent : node)) {
-                error(node, Diagnostics._0_is_declared_but_its_value_is_never_read, name);
+                diagnostics.add(createDiagnosticForNodeSpan(getSourceFileOfNode(declaration), declaration, node, Diagnostics._0_is_declared_but_its_value_is_never_read, name));
             }
         }
 
@@ -21623,7 +21623,7 @@ namespace ts {
         }
 
         function isIdentifierThatStartsWithUnderScore(node: Node) {
-            return node.kind === SyntaxKind.Identifier && idText(<Identifier>node).charCodeAt(0) === CharacterCodes._;
+            return isIdentifier(node) && idText(node).charCodeAt(0) === CharacterCodes._;
         }
 
         function checkUnusedClassMembers(node: ClassDeclaration | ClassExpression): void {

src/compiler/utilities.ts

@@ -607,6 +607,11 @@ namespace ts {
         return createFileDiagnostic(sourceFile, span.start, span.length, message, arg0, arg1, arg2, arg3);
     }
 
+    export function createDiagnosticForNodeSpan(sourceFile: SourceFile, startNode: Node, endNode: Node, message: DiagnosticMessage, arg0?: string | number, arg1?: string | number, arg2?: string | number, arg3?: string | number): Diagnostic {
+        const start = skipTrivia(sourceFile.text, startNode.pos);
+        return createFileDiagnostic(sourceFile, start, endNode.end - start, message, arg0, arg1, arg2, arg3);
+    }
+
     export function createDiagnosticForNodeFromMessageChain(node: Node, messageChain: DiagnosticMessageChain): Diagnostic {
         const sourceFile = getSourceFileOfNode(node);
         const span = getErrorSpanForNode(sourceFile, node);

src/services/codefixes/fixUnusedIdentifier.ts

@@ -10,7 +10,7 @@ namespace ts.codefix {
         errorCodes,
         getCodeActions(context) {
             const { sourceFile } = context;
-            const token = getToken(sourceFile, context.span.start);
+            const token = getToken(sourceFile, textSpanEnd(context.span));
             const result: CodeFixAction[] = [];
 
             const deletion = textChanges.ChangeTracker.with(context, t => tryDeleteDeclaration(t, sourceFile, token));
@@ -30,7 +30,7 @@ namespace ts.codefix {
         fixIds: [fixIdPrefix, fixIdDelete],
         getAllCodeActions: context => codeFixAll(context, errorCodes, (changes, diag) => {
             const { sourceFile } = context;
-            const token = getToken(diag.file!, diag.start!);
+            const token = findPrecedingToken(textSpanEnd(diag), diag.file!);
             switch (context.fixId) {
                 case fixIdPrefix:
                     if (isIdentifier(token) && canPrefix(token)) {
@@ -47,9 +47,9 @@ namespace ts.codefix {
     });
 
     function getToken(sourceFile: SourceFile, pos: number): Node {
-        const token = getTokenAtPosition(sourceFile, pos, /*includeJsDocComment*/ false);
+        const token = findPrecedingToken(pos, sourceFile);
         // this handles var ["computed"] = 12;
-        return token.kind === SyntaxKind.OpenBracketToken ? getTokenAtPosition(sourceFile, pos + 1, /*includeJsDocComment*/ false) : token;
+        return token.kind === SyntaxKind.CloseBracketToken ? findPrecedingToken(pos - 1, sourceFile) : token;
     }
 
     function tryPrefixDeclaration(changes: textChanges.ChangeTracker, errorCode: number, sourceFile: SourceFile, token: Node): void {