function enterFunction(node) {
			lexicalScopeStack.unshift(new Set());
			sourceCode
				.getScope(node)
				.variables.filter(variable => variable.name === "arguments")
				.forEach(variable => {
					variable.references
						.map(ref => ref.identifier)
						.forEach(identifier =>
							argumentsIdentifiers.add(identifier),
						);
				});
		}
Enters a function. This creates a new lexical identifier scope, so a new Set of arrow functions is pushed onto the stack.
Also, this marks all `arguments` identifiers so that they can be detected later.
@param {ASTNode} node The node representing the function.
@returns {void}