diff --git a/compiler/rustc_lint/src/reference_casting.rs b/compiler/rustc_lint/src/reference_casting.rs index b80e90c25a334..34153e3a220d3 100644 --- a/compiler/rustc_lint/src/reference_casting.rs +++ b/compiler/rustc_lint/src/reference_casting.rs @@ -202,8 +202,10 @@ fn is_cast_to_bigger_memory_layout<'tcx>( // if the current expr looks like this `&mut expr[index]` then just looking // at `expr[index]` won't give us the underlying allocation, so we just skip it - // the same logic applies field access like `&mut expr.field` - if let ExprKind::Index(..) | ExprKind::Field(..) = e_alloc.kind { + // the same logic applies field access `&mut expr.field` and reborrows `&mut *expr`. + if let ExprKind::Index(..) | ExprKind::Field(..) | ExprKind::Unary(UnOp::Deref, ..) = + e_alloc.kind + { return None; } diff --git a/tests/ui/lint/reference_casting.rs b/tests/ui/lint/reference_casting.rs index 87a682249b00f..87fa42f94775e 100644 --- a/tests/ui/lint/reference_casting.rs +++ b/tests/ui/lint/reference_casting.rs @@ -261,6 +261,13 @@ unsafe fn bigger_layout() { let ptr = r as *mut i32 as *mut Vec3; unsafe { *ptr = Vec3(0, 0, 0) } } + + unsafe fn deref(v: &mut Vec3) { + let r = &mut v.0; + let r = &mut *r; + let ptr = &mut *(r as *mut i32 as *mut Vec3); + unsafe { *ptr = Vec3(0, 0, 0) } + } } const RAW_PTR: *mut u8 = 1 as *mut u8;