fix: handle const Type Parameters (#519)

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## PR Checklist

- [x] Addresses an existing open issue: fixes #518
- [x] That issue was marked as [`status: accepting
prs`](https://github.com/JoshuaKGoldberg/ts-api-utils/issues?q=is%3Aopen+is%3Aissue+label%3A%22status%3A+accepting+prs%22)
- [x] Steps in
[CONTRIBUTING.md](https://github.com/JoshuaKGoldberg/ts-api-utils/blob/main/.github/CONTRIBUTING.md)
were taken

## Overview

Initial attempt at resolving the issue.
I've got no idea if this is the correct approach or not.
There might be some cases which this PR doesn't currently handle.

---------

Co-authored-by: Josh Goldberg ✨ <git@joshuakgoldberg.com>

Author: RebeccaStevens

package.json

@@ -53,6 +53,7 @@
 		"@phenomnomnominal/tsquery": "^6.1.3",
 		"@release-it/conventional-changelog": "^8.0.1",
 		"@types/eslint": "^8.56.5",
+		"@types/semver": "^7.5.8",
 		"@typescript-eslint/eslint-plugin": "^7.3.1",
 		"@typescript-eslint/parser": "^7.3.1",
 		"@typescript/vfs": "^1.5.0",
@@ -81,6 +82,7 @@
 		"prettier-plugin-curly": "^0.2.1",
 		"prettier-plugin-packagejson": "^2.4.7",
 		"release-it": "^17.0.1",
+		"semver": "^7.6.2",
 		"sentences-per-line": "^0.2.1",
 		"should-semantic-release": "^0.3.0",
 		"tsup": "^8.0.2",

pnpm-lock.yaml

@@ -89,6 +89,17 @@ export const isSymbolFlagSet: (
 	flag: ts.SymbolFlags,
 ) => boolean = isFlagSetOnObject;
 
+/**
+ * Test if the given symbol's links has the given `CheckFlags` set.
+ * @internal
+ */
+export function isTransientSymbolLinksFlagSet(
+	links: ts.TransientSymbolLinks,
+	flag: ts.CheckFlags,
+): boolean {
+	return isFlagSet(links.checkFlags, flag);
+}
+
 /**
  * Test if the given node has the given `TypeFlags` set.
  * @category Nodes - Flag Utilities

src/flags.ts

@@ -3,6 +3,7 @@
 
 import ts from "typescript";
 
+import { isTransientSymbolLinksFlagSet } from "../flags";
 import {
 	isConstAssertionExpression,
 	isEntityNameExpression,
@@ -28,10 +29,13 @@ export function isBindableObjectDefinePropertyCall(
 }
 
 /**
- * Detects whether an expression is affected by an enclosing `as const` assertion and therefore treated literally.
+ * Detects whether the property assignment is affected by an enclosing `as const` assertion or const type parameter and therefore treated literally.
  * @internal
  */
-export function isInConstContext(node: ts.Expression): boolean {
+export function isInConstContext(
+	node: ts.PropertyAssignment | ts.ShorthandPropertyAssignment,
+	typeChecker: ts.TypeChecker,
+): boolean {
 	let current: ts.Node = node;
 	while (true) {
 		const parent = current.parent;
@@ -69,6 +73,45 @@ export function isInConstContext(node: ts.Expression): boolean {
 			case ts.SyntaxKind.TemplateExpression:
 				current = parent;
 				break;
+			case ts.SyntaxKind.CallExpression:
+				if (!ts.isExpression(current)) {
+					return false;
+				}
+
+				const functionSignature = typeChecker.getResolvedSignature(
+					parent as ts.CallExpression,
+				);
+				if (functionSignature === undefined) {
+					return false;
+				}
+
+				const argumentIndex = (parent as ts.CallExpression).arguments.indexOf(
+					current,
+				);
+				if (argumentIndex < 0) {
+					return false;
+				}
+
+				const parameterSymbol =
+					functionSignature.getParameters()[argumentIndex];
+				if (parameterSymbol === undefined || !("links" in parameterSymbol)) {
+					return false;
+				}
+
+				const parameterSymbolLinks = (parameterSymbol as ts.TransientSymbol)
+					.links;
+
+				const propertySymbol =
+					parameterSymbolLinks.type?.getProperties()?.[argumentIndex];
+				if (propertySymbol === undefined || !("links" in propertySymbol)) {
+					return false;
+				}
+
+				// I believe we only need to check one level deep, regardless of how deep `node` is.
+				return isTransientSymbolLinksFlagSet(
+					(propertySymbol as ts.TransientSymbol).links,
+					ts.CheckFlags.Readonly,
+				);
 			default:
 				return false;
 		}