-use crate::utils::is_adjusted;
-use crate::utils::span_lint;
-use rustc::declare_lint_pass;
-use rustc::hir::def::{DefKind, Res};
-use rustc::hir::{Expr, ExprKind};
-use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use rustc_session::declare_tool_lint;
+use clippy_utils::diagnostics::span_lint;
+use clippy_utils::is_adjusted;
+use rustc_hir::{Expr, ExprKind};
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
declare_clippy_lint! {
- /// **What it does:** Checks for construction of a structure or tuple just to
+ /// ### What it does
+ /// Checks for construction of a structure or tuple just to
/// assign a value in it.
///
- /// **Why is this bad?** Readability. If the structure is only created to be
+ /// ### Why is this bad?
+ /// Readability. If the structure is only created to be
/// updated, why not write the structure you want in the first place?
///
- /// **Known problems:** None.
- ///
- /// **Example:**
+ /// ### Example
/// ```rust
/// (0, 0).0 = 1
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub TEMPORARY_ASSIGNMENT,
complexity,
"assignments to temporaries"
}
-fn is_temporary(cx: &LateContext<'_, '_>, expr: &Expr<'_>) -> bool {
- match &expr.kind {
- ExprKind::Struct(..) | ExprKind::Tup(..) => true,
- ExprKind::Path(qpath) => {
- if let Res::Def(DefKind::Const, ..) = cx.tables.qpath_res(qpath, expr.hir_id) {
- true
- } else {
- false
- }
- },
- _ => false,
- }
+fn is_temporary(expr: &Expr<'_>) -> bool {
+ matches!(&expr.kind, ExprKind::Struct(..) | ExprKind::Tup(..))
}
declare_lint_pass!(TemporaryAssignment => [TEMPORARY_ASSIGNMENT]);
-impl<'a, 'tcx> LateLintPass<'a, 'tcx> for TemporaryAssignment {
- fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_>) {
+impl<'tcx> LateLintPass<'tcx> for TemporaryAssignment {
+ fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
if let ExprKind::Assign(target, ..) = &expr.kind {
let mut base = target;
while let ExprKind::Field(f, _) | ExprKind::Index(f, _) = &base.kind {
base = f;
}
- if is_temporary(cx, base) && !is_adjusted(cx, base) {
+ if is_temporary(base) && !is_adjusted(cx, base) {
span_lint(cx, TEMPORARY_ASSIGNMENT, expr.span, "assignment to temporary");
}
}