fix: Deprecation error message reporting method type as deprecated instead...

[arnavnagzirkar]

Summary

Root Cause

In src/compiler/checker.ts, the function addDeprecatedSuggestionWithSignature was missing a check for when deprecatedEntity is undefined but location is an Identifier. In that case, it fell through to use signatureString (the full function type like (): ZodObject<...>) as the deprecated entity name in the diagnostic message.

This happens when calling a deprecated method on the result of a chained call (e.g., createBuilder().configure("x").oldMethod()). In this pattern, tryGetPropertyAccessOrIdentifierToString returns undefined because the base of the property access is a CallExpression (not an identifier or simple property access). As a result, name/deprecatedEntity is undefined. Without the identifier check, the code would fall through and use signatureString in the message.

Change Made

src/compiler/checker.ts — Added an isIdentifier(location) branch in addDeprecatedSuggestionWithSignature:

// Before:
const diagnostic = deprecatedEntity
    ? createDiagnosticForNode(location, Diagnostics.The_signature_0_of_1_is_deprecated, signatureString, deprecatedEntity)
    : createDiagnosticForNode(location, Diagnostics._0_is_deprecated, signatureString);

// After:
const diagnostic = deprecatedEntity
    ? createDiagnosticForNode(location, Diagnostics.The_signature_0_of_1_is_deprecated, signatureString, deprecatedEntity)
    : isIdentifier(location)
    ? createDiagnosticForNode(location, Diagnostics._0_is_deprecated, idText(location))
    : createDiagnosticForNode(location, Diagnostics._0_is_deprecated, signatureString);

When deprecatedEntity is undefined and the suggestion node is an identifier (e.g., the method name oldMethod), we now use idText(location) (the identifier text) instead of signatureString (the type signature). This produces 'oldMethod' is deprecated instead of '(): void' is deprecated.

Issue

Fixes #62396

Issue URL: #62396

Changes

src/compiler/checker.ts                            |  2 +
 .../deprecatedMethodOnChainedCall.errors.txt       | 22 +++++++++++
 .../deprecatedMethodOnChainedCall.symbols          | 32 +++++++++++++++
 .../reference/deprecatedMethodOnChainedCall.types  | 45 ++++++++++++++++++++++
 .../compiler/deprecatedMethodOnChainedCall.ts      | 17 ++++++++
 5 files changed, 118 insertions(+)

Testing

• Agent ran relevant tests during development

• Linting checks passed

• Changes are minimal and focused on the issue

AI Assistance Disclosure

This PR was authored with the assistance of AI coding tools (GitHub Copilot). I have read and understand the change and will respond to review feedback myself.

[RyanCavanaugh]

#63521 (comment)