diff --git a/compiler/rustc_passes/src/dead.rs b/compiler/rustc_passes/src/dead.rs index fa9d0c7b1b7d4..d5d7cc5dc2e1a 100644 --- a/compiler/rustc_passes/src/dead.rs +++ b/compiler/rustc_passes/src/dead.rs @@ -172,7 +172,6 @@ impl<'tcx> MarkSymbolVisitor<'tcx> { } } - #[allow(dead_code)] // FIXME(81658): should be used + lint reinstated after #83171 relands. fn handle_assign(&mut self, expr: &'tcx hir::Expr<'tcx>) { if self .typeck_results() @@ -189,7 +188,6 @@ impl<'tcx> MarkSymbolVisitor<'tcx> { } } - #[allow(dead_code)] // FIXME(81658): should be used + lint reinstated after #83171 relands. fn check_for_self_assign(&mut self, assign: &'tcx hir::Expr<'tcx>) { fn check_for_self_assign_helper<'tcx>( typeck_results: &'tcx ty::TypeckResults<'tcx>, @@ -576,6 +574,10 @@ impl<'tcx> Visitor<'tcx> for MarkSymbolVisitor<'tcx> { hir::ExprKind::OffsetOf(..) => { self.handle_offset_of(expr); } + hir::ExprKind::Assign(ref lhs, ..) => { + self.handle_assign(lhs); + self.check_for_self_assign(expr); + } _ => (), } diff --git a/tests/ui/lint/dead-code/self-assign.rs b/tests/ui/lint/dead-code/self-assign.rs index 357846baf2212..ce91f53cbf1e1 100644 --- a/tests/ui/lint/dead-code/self-assign.rs +++ b/tests/ui/lint/dead-code/self-assign.rs @@ -7,23 +7,20 @@ //! - `dead_code` lint expansion for self-assignments was implemented in #87129. //! - Unfortunately implementation components of #87129 had to be disabled as part of reverts //! #86212, #83171 (to revert #81473) to address regressions #81626 and #81658. -//! - Consequently, none of the following warnings are emitted. +//! - Re-enabled in current version to properly detect self-assignments. //@ check-pass -// Implementation of self-assignment `dead_code` lint expansions disabled due to reverts. -//@ known-bug: #75356 - #![allow(unused_assignments)] #![warn(dead_code)] fn main() { let mut x = 0; x = x; - // FIXME ~^ WARNING: useless assignment of variable of type `i32` to itself + //~^ WARNING: useless assignment of variable of type `i32` to itself x = (x); - // FIXME ~^ WARNING: useless assignment of variable of type `i32` to itself + //~^ WARNING: useless assignment of variable of type `i32` to itself x = {x}; // block expressions don't count as self-assignments @@ -32,10 +29,10 @@ fn main() { struct S<'a> { f: &'a str } let mut s = S { f: "abc" }; s = s; - // FIXME ~^ WARNING: useless assignment of variable of type `S` to itself + //~^ WARNING: useless assignment of variable of type `S<'_>` to itself s.f = s.f; - // FIXME ~^ WARNING: useless assignment of field of type `&str` to itself + //~^ WARNING: useless assignment of field of type `&str` to itself struct N0 { x: Box } @@ -44,11 +41,11 @@ fn main() { struct N3 { n: N2 }; let mut n3 = N3 { n: N2(N1 { n: N0 { x: Box::new(42) } }) }; n3.n.0.n.x = n3.n.0.n.x; - // FIXME ~^ WARNING: useless assignment of field of type `Box` to itself + //~^ WARNING: useless assignment of field of type `Box` to itself let mut t = (1, ((2, 3, (4, 5)),)); t.1.0.2.1 = t.1.0.2.1; - // FIXME ~^ WARNING: useless assignment of field of type `i32` to itself + //~^ WARNING: useless assignment of field of type `i32` to itself let mut y = 0; diff --git a/tests/ui/lint/dead-code/self-assign.stderr b/tests/ui/lint/dead-code/self-assign.stderr new file mode 100644 index 0000000000000..408ebdb658b5a --- /dev/null +++ b/tests/ui/lint/dead-code/self-assign.stderr @@ -0,0 +1,44 @@ +warning: useless assignment of variable of type `i32` to itself + --> $DIR/self-assign.rs:19:5 + | +LL | x = x; + | ^^^^^ + | +note: the lint level is defined here + --> $DIR/self-assign.rs:15:9 + | +LL | #![warn(dead_code)] + | ^^^^^^^^^ + +warning: useless assignment of variable of type `i32` to itself + --> $DIR/self-assign.rs:22:5 + | +LL | x = (x); + | ^^^^^^^ + +warning: useless assignment of variable of type `S<'_>` to itself + --> $DIR/self-assign.rs:31:5 + | +LL | s = s; + | ^^^^^ + +warning: useless assignment of field of type `&str` to itself + --> $DIR/self-assign.rs:34:5 + | +LL | s.f = s.f; + | ^^^^^^^^^ + +warning: useless assignment of field of type `Box` to itself + --> $DIR/self-assign.rs:43:5 + | +LL | n3.n.0.n.x = n3.n.0.n.x; + | ^^^^^^^^^^^^^^^^^^^^^^^ + +warning: useless assignment of field of type `i32` to itself + --> $DIR/self-assign.rs:47:5 + | +LL | t.1.0.2.1 = t.1.0.2.1; + | ^^^^^^^^^^^^^^^^^^^^^ + +warning: 6 warnings emitted +