--- /dev/null
+use crate::utils::{is_adjusted, span_lint};
+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
+ /// assign a value in it.
+ ///
+ /// **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:**
+ /// ```rust
+ /// (0, 0).0 = 1
+ /// ```
+ pub TEMPORARY_ASSIGNMENT,
+ complexity,
+ "assignments to temporaries"
+}
+
+fn is_temporary(expr: &Expr<'_>) -> bool {
+ matches!(&expr.kind, ExprKind::Struct(..) | ExprKind::Tup(..))
+}
+
+declare_lint_pass!(TemporaryAssignment => [TEMPORARY_ASSIGNMENT]);
+
+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(base) && !is_adjusted(cx, base) {
+ span_lint(cx, TEMPORARY_ASSIGNMENT, expr.span, "assignment to temporary");
+ }
+ }
+ }
+}