declare_clippy_lint! {
/// **What it does:** Checks for usage of `option.map(f)` where f is a function
- /// or closure that returns the unit type.
+ /// or closure that returns the unit type `()`.
///
/// **Why is this bad?** Readability, this can be written more clearly with
/// an if let statement
declare_clippy_lint! {
/// **What it does:** Checks for usage of `result.map(f)` where f is a function
- /// or closure that returns the unit type.
+ /// or closure that returns the unit type `()`.
///
/// **Why is this bad?** Readability, this can be written more clearly with
/// an if let statement
declare_lint_pass!(MapUnit => [OPTION_MAP_UNIT_FN, RESULT_MAP_UNIT_FN]);
fn is_unit_type(ty: Ty<'_>) -> bool {
- match ty.kind {
+ match ty.kind() {
ty::Tuple(slice) => slice.is_empty(),
ty::Never => true,
_ => false,
}
fn is_unit_function(cx: &LateContext<'_>, expr: &hir::Expr<'_>) -> bool {
- let ty = cx.tables().expr_ty(expr);
+ let ty = cx.typeck_results().expr_ty(expr);
- if let ty::FnDef(id, _) = ty.kind {
+ if let ty::FnDef(id, _) = *ty.kind() {
if let Some(fn_type) = cx.tcx.fn_sig(id).no_bound_vars() {
return is_unit_type(fn_type.output());
}
}
fn is_unit_expression(cx: &LateContext<'_>, expr: &hir::Expr<'_>) -> bool {
- is_unit_type(cx.tables().expr_ty(expr))
+ is_unit_type(cx.typeck_results().expr_ty(expr))
}
/// The expression inside a closure may or may not have surrounding braces and
#[must_use]
fn suggestion_msg(function_type: &str, map_type: &str) -> String {
format!(
- "called `map(f)` on an `{0}` value where `f` is a {1} that returns the unit type",
+ "called `map(f)` on an `{0}` value where `f` is a {1} that returns the unit type `()`",
map_type, function_type
)
}
fn lint_map_unit_fn(cx: &LateContext<'_>, stmt: &hir::Stmt<'_>, expr: &hir::Expr<'_>, map_args: &[hir::Expr<'_>]) {
let var_arg = &map_args[0];
- let (map_type, variant, lint) = if is_type_diagnostic_item(cx, cx.tables().expr_ty(var_arg), sym!(option_type)) {
- ("Option", "Some", OPTION_MAP_UNIT_FN)
- } else if is_type_diagnostic_item(cx, cx.tables().expr_ty(var_arg), sym!(result_type)) {
- ("Result", "Ok", RESULT_MAP_UNIT_FN)
- } else {
- return;
- };
+ let (map_type, variant, lint) =
+ if is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(var_arg), sym!(option_type)) {
+ ("Option", "Some", OPTION_MAP_UNIT_FN)
+ } else if is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(var_arg), sym!(result_type)) {
+ ("Result", "Ok", RESULT_MAP_UNIT_FN)
+ } else {
+ return;
+ };
let fn_arg = &map_args[1];
if is_unit_function(cx, fn_arg) {