diff --git a/clippy_lints/src/transmute/transmuting_null.rs b/clippy_lints/src/transmute/transmuting_null.rs index 31e770f421e1..3f435f255d91 100644 --- a/clippy_lints/src/transmute/transmuting_null.rs +++ b/clippy_lints/src/transmute/transmuting_null.rs @@ -2,7 +2,7 @@ use clippy_utils::consts::{ConstEvalCtxt, Constant}; use clippy_utils::diagnostics::span_lint; use clippy_utils::is_integer_const; use clippy_utils::res::{MaybeDef, MaybeResPath}; -use rustc_hir::{Expr, ExprKind}; +use rustc_hir::{ConstBlock, Expr, ExprKind}; use rustc_lint::LateContext; use rustc_middle::ty::Ty; use rustc_span::symbol::sym; @@ -42,5 +42,23 @@ pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, arg: &'t return true; } + // Catching: + // `std::mem::transmute({ 0 as *const u64 })` and similar const blocks + if let ExprKind::Block(block, _) = arg.kind + && block.stmts.is_empty() + && let Some(inner) = block.expr + { + // Run again with the inner expression + return check(cx, expr, inner, to_ty); + } + + // Catching: + // `std::mem::transmute(const { u64::MIN as *const u64 });` + if let ExprKind::ConstBlock(ConstBlock { body, .. }) = arg.kind { + // Strip out the const and run again + let block = cx.tcx.hir_body(body).value; + return check(cx, expr, block, to_ty); + } + false } diff --git a/tests/ui/transmuting_null.rs b/tests/ui/transmuting_null.rs index 0d3b26673452..00aa35dff803 100644 --- a/tests/ui/transmuting_null.rs +++ b/tests/ui/transmuting_null.rs @@ -37,8 +37,19 @@ fn transmute_const_int() { } } +fn transumute_single_expr_blocks() { + unsafe { + let _: &u64 = std::mem::transmute({ 0 as *const u64 }); + //~^ transmuting_null + + let _: &u64 = std::mem::transmute(const { u64::MIN as *const u64 }); + //~^ transmuting_null + } +} + fn main() { one_liners(); transmute_const(); transmute_const_int(); + transumute_single_expr_blocks(); } diff --git a/tests/ui/transmuting_null.stderr b/tests/ui/transmuting_null.stderr index ed7c3396a243..e1de391813bd 100644 --- a/tests/ui/transmuting_null.stderr +++ b/tests/ui/transmuting_null.stderr @@ -25,5 +25,17 @@ error: transmuting a known null pointer into a reference LL | let _: &u64 = std::mem::transmute(u64::MIN as *const u64); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ -error: aborting due to 4 previous errors +error: transmuting a known null pointer into a reference + --> tests/ui/transmuting_null.rs:42:23 + | +LL | let _: &u64 = std::mem::transmute({ 0 as *const u64 }); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +error: transmuting a known null pointer into a reference + --> tests/ui/transmuting_null.rs:45:23 + | +LL | let _: &u64 = std::mem::transmute(const { u64::MIN as *const u64 }); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +error: aborting due to 6 previous errors