extensions/typescript-language-features/src/languageFeatures/diagnostics.ts/FileDiagnostics/delete
class FileDiagnostics:	public delete(toDelete: vscode.Diagnostic): void {
		for (const [type, diags] of this._diagnostics) {
			this._diagnostics.set(type, diags.filter(diag => !diagnosticsEquals(diag, toDelete)));
		}
	}