use super::utils::{get_arg_name, match_var, remove_blocks, snippet_with_applicability, span_lint_and_sugg};
use if_chain::if_chain;
+use rustc::declare_lint_pass;
use rustc::hir::*;
use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use rustc::{declare_tool_lint, lint_array};
use rustc_errors::Applicability;
+use rustc_session::declare_tool_lint;
-/// **What it does:** Checks for matches being used to destructure a single-variant enum
-/// or tuple struct where a `let` will suffice.
-///
-/// **Why is this bad?** Just readability – `let` doesn't nest, whereas a `match` does.
-///
-/// **Known problems:** None.
-///
-/// **Example:**
-/// ```rust
-/// enum Wrapper {
-/// Data(i32),
-/// }
-///
-/// let wrapper = Wrapper::Data(42);
-///
-/// let data = match wrapper {
-/// Wrapper::Data(i) => i,
-/// };
-/// ```
-///
-/// The correct use would be:
-/// ```rust
-/// enum Wrapper {
-/// Data(i32),
-/// }
-///
-/// let wrapper = Wrapper::Data(42);
-/// let Wrapper::Data(data) = wrapper;
-/// ```
declare_clippy_lint! {
+ /// **What it does:** Checks for matches being used to destructure a single-variant enum
+ /// or tuple struct where a `let` will suffice.
+ ///
+ /// **Why is this bad?** Just readability – `let` doesn't nest, whereas a `match` does.
+ ///
+ /// **Known problems:** None.
+ ///
+ /// **Example:**
+ /// ```rust
+ /// enum Wrapper {
+ /// Data(i32),
+ /// }
+ ///
+ /// let wrapper = Wrapper::Data(42);
+ ///
+ /// let data = match wrapper {
+ /// Wrapper::Data(i) => i,
+ /// };
+ /// ```
+ ///
+ /// The correct use would be:
+ /// ```rust
+ /// enum Wrapper {
+ /// Data(i32),
+ /// }
+ ///
+ /// let wrapper = Wrapper::Data(42);
+ /// let Wrapper::Data(data) = wrapper;
+ /// ```
pub INFALLIBLE_DESTRUCTURING_MATCH,
style,
"a match statement with a single infallible arm instead of a `let`"
}
-#[derive(Copy, Clone, Default)]
-pub struct Pass;
+declare_lint_pass!(InfallibleDestructingMatch => [INFALLIBLE_DESTRUCTURING_MATCH]);
-impl LintPass for Pass {
- fn get_lints(&self) -> LintArray {
- lint_array!(INFALLIBLE_DESTRUCTURING_MATCH)
- }
-
- fn name(&self) -> &'static str {
- "InfallibleDestructingMatch"
- }
-}
-
-impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass {
+impl<'a, 'tcx> LateLintPass<'a, 'tcx> for InfallibleDestructingMatch {
fn check_local(&mut self, cx: &LateContext<'a, 'tcx>, local: &'tcx Local) {
if_chain! {
if let Some(ref expr) = local.init;
- if let ExprKind::Match(ref target, ref arms, MatchSource::Normal) = expr.node;
- if arms.len() == 1 && arms[0].pats.len() == 1 && arms[0].guard.is_none();
- if let PatKind::TupleStruct(QPath::Resolved(None, ref variant_name), ref args, _) = arms[0].pats[0].node;
+ if let ExprKind::Match(ref target, ref arms, MatchSource::Normal) = expr.kind;
+ if arms.len() == 1 && arms[0].guard.is_none();
+ if let PatKind::TupleStruct(QPath::Resolved(None, ref variant_name), ref args, _) = arms[0].pat.kind;
if args.len() == 1;
if let Some(arg) = get_arg_name(&args[0]);
let body = remove_blocks(&arms[0].body);