fix: crash in getWellKnownSymbolPropertyOfType for mapped typeof symbol

[JoshuaKGoldberg]

PR Checklist

• Addresses an existing open issue: fixes Bug: Crash on interaction between no-misused-spread and SystemStyleObject from Chakra UI v2 typescript-eslint/typescript-eslint#10747
• That issue was marked as status: accepting prs
• Steps in CONTRIBUTING.md were taken

Overview

As seen in typescript-eslint/typescript-eslint#10747, we can't assume that prop's declarations array can be found. If the type being checked is a mapped type over the requested well-known symbol, it'll come up as undefined.

💖

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 77.20%. Comparing base (07a2d18) to head (b64081a).
Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #698      +/-   ##
==========================================
+ Coverage   76.98%   77.20%   +0.21%     
==========================================
  Files          50       50              
  Lines        4979     5000      +21     
  Branches      680      687       +7     
==========================================
+ Hits         3833     3860      +27     
+ Misses       1145     1139       -6     
  Partials        1        1              

Flag	Coverage Δ
4.8.4	74.56% <100.00%> (+0.22%)	⬆️
latest	76.78% <100.00%> (+0.21%)	⬆️

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[ronami]

👍👍👍

[ronami]

Wdyt about adding the following (or similar) to createSourceFileAndTypeChecker() so issues like this would be easier to notice (probably on a separate PR, I'll be happy to send one):

export function createSourceFileAndTypeChecker(
	sourceText: string,
	fileName = "file.tsx",
): SourceFileAndTypeChecker {
	const compilerOptions: ts.CompilerOptions = {
		lib: ["ES2018"],
		target: ts.ScriptTarget.ES2018,
	};

	const fsMap = tsvfs.createDefaultMapFromNodeModules(compilerOptions, ts);
	fsMap.set(fileName, sourceText);

	const system = tsvfs.createSystem(fsMap);
	const env = tsvfs.createVirtualTypeScriptEnvironment(
		system,
		[fileName],
		ts,
		compilerOptions,
	);

	const program = env.languageService.getProgram();

	if (program === undefined) {
		throw new Error("Failed to get program.");
	}

+ 	const diagnostics = program.getSyntacticDiagnostics();
+ 
+ 	if (diagnostics.length > 0) {
+ 		throw new Error(
+ 			ts.flattenDiagnosticMessageText(
+ 				diagnostics[0].messageText,
+ 				ts.sys.newLine,
+ 			),
+ 		);
+ 	}

	return {
		sourceFile: program.getSourceFile(fileName)!,
		typeChecker: program.getTypeChecker(),
	};
}

[JoshuaKGoldberg]

Good idea, I'd like that!