-use crate::utils::{is_type_diagnostic_item, iter_input_pats, method_chain_args, snippet, span_lint_and_then};
+use clippy_utils::diagnostics::span_lint_and_then;
+use clippy_utils::source::snippet;
+use clippy_utils::ty::is_type_diagnostic_item;
+use clippy_utils::{iter_input_pats, method_chain_args};
use if_chain::if_chain;
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_span::sym;
declare_clippy_lint! {
- /// **What it does:** Checks for usage of `option.map(f)` where f is a function
+ /// ### What it does
+ /// Checks for usage of `option.map(f)` where f is a function
/// or closure that returns the unit type `()`.
///
- /// **Why is this bad?** Readability, this can be written more clearly with
+ /// ### Why is this bad?
+ /// Readability, this can be written more clearly with
/// an if let statement
///
- /// **Known problems:** None.
- ///
- /// **Example:**
- ///
+ /// ### Example
/// ```rust
/// # fn do_stuff() -> Option<String> { Some(String::new()) }
/// # fn log_err_msg(foo: String) -> Option<String> { Some(foo) }
/// log_err_msg(format_msg(msg));
/// }
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub OPTION_MAP_UNIT_FN,
complexity,
"using `option.map(f)`, where `f` is a function or closure that returns `()`"
}
declare_clippy_lint! {
- /// **What it does:** Checks for usage of `result.map(f)` where f is a function
+ /// ### What it does
+ /// Checks for usage of `result.map(f)` where f is a function
/// or closure that returns the unit type `()`.
///
- /// **Why is this bad?** Readability, this can be written more clearly with
+ /// ### Why is this bad?
+ /// Readability, this can be written more clearly with
/// an if let statement
///
- /// **Known problems:** None.
- ///
- /// **Example:**
- ///
+ /// ### Example
/// ```rust
/// # fn do_stuff() -> Result<String, String> { Ok(String::new()) }
/// # fn log_err_msg(foo: String) -> Result<String, String> { Ok(foo) }
/// log_err_msg(format_msg(msg));
/// };
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub RESULT_MAP_UNIT_FN,
complexity,
"using `result.map(f)`, where `f` is a function or closure that returns `()`"
// Calls can't be reduced any more
Some(expr.span)
},
- hir::ExprKind::Block(ref block, _) => {
- match (&block.stmts[..], block.expr.as_ref()) {
+ hir::ExprKind::Block(block, _) => {
+ match (block.stmts, block.expr.as_ref()) {
(&[], Some(inner_expr)) => {
// If block only contains an expression,
// reduce `{ X }` to `X`
// If block only contains statements,
// reduce `{ X; }` to `X` or `X;`
match inner_stmt.kind {
- hir::StmtKind::Local(ref local) => Some(local.span),
- hir::StmtKind::Expr(ref e) => Some(e.span),
+ hir::StmtKind::Local(local) => Some(local.span),
+ hir::StmtKind::Expr(e) => Some(e.span),
hir::StmtKind::Semi(..) => Some(inner_stmt.span),
hir::StmtKind::Item(..) => None,
}
cx: &LateContext<'tcx>,
expr: &hir::Expr<'_>,
) -> Option<(&'tcx hir::Param<'tcx>, &'tcx hir::Expr<'tcx>)> {
- if let hir::ExprKind::Closure(_, ref decl, inner_expr_id, _, _) = expr.kind {
+ if_chain! {
+ if let hir::ExprKind::Closure(_, decl, inner_expr_id, _, _) = expr.kind;
let body = cx.tcx.hir().body(inner_expr_id);
let body_expr = &body.value;
-
- if_chain! {
- if decl.inputs.len() == 1;
- if is_unit_expression(cx, body_expr);
- if let Some(binding) = iter_input_pats(&decl, body).next();
- then {
- return Some((binding, body_expr));
- }
+ if decl.inputs.len() == 1;
+ if is_unit_expression(cx, body_expr);
+ if let Some(binding) = iter_input_pats(decl, body).next();
+ then {
+ return Some((binding, body_expr));
}
}
None
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.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 (map_type, variant, lint) = if is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(var_arg), sym::Option) {
+ ("Option", "Some", OPTION_MAP_UNIT_FN)
+ } else if is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(var_arg), sym::Result) {
+ ("Result", "Ok", RESULT_MAP_UNIT_FN)
+ } else {
+ return;
+ };
let fn_arg = &map_args[1];
if is_unit_function(cx, fn_arg) {
return;
}
- if let hir::StmtKind::Semi(ref expr) = stmt.kind {
+ if let hir::StmtKind::Semi(expr) = stmt.kind {
if let Some(arglists) = method_chain_args(expr, &["map"]) {
lint_map_unit_fn(cx, stmt, expr, arglists[0]);
}