Poor error recovery when `enum` is used as a parameter name

TypeScript Version: 3.6.2

Search Terms: expression expected reserved word

Code

function converter<Enum>(values: string[], enums: Enum[]): Map<Enum, string> {
	return new Map<Enum, string>(
		enums.map((enum: Enum, index: number) => [ enum, values[index] ])
	);
}

Expected behavior:
After some confusion why this displays so many red curlies, the error should make it clear to me that the reserved word enum is accidentaly being used as an argument name. An error is given on enum saying something along the lines of You cannot use enum as a variable/argument because it is a reserved word.

Actual behavior:
After a LOT of confusion, one realizes that the reserved word enum is accidentally being used as an argument name. An error is given on several parts in the above code, where the most helpful one is Expression expected (ts1109), which is just unnecesarily confusing.

Playground Link

Related Issues:
None that seem related.

提供されたコードを TypeScript 3.6.2 Playground で使って診断を再現し、その後、パラメーター名 enum 周辺で発生する parser のエラーを比較します。予約語の誤用を特定しつつ、混乱を招く連鎖的な診断を発生させないように報告されるエラーを改善し、同じ例で結果を検証します。