mirror of
https://github.com/rust-lang/rust-clippy
synced 2024-12-18 09:03:18 +00:00
Correctly handle transmute as return value from block and let var: _ = transmute
This commit is contained in:
Guillaume Gomez
parent
8e0496170d
commit
ffa12798c0
4 changed files with 64 additions and 15 deletions
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@ -1,5 +1,5 @@
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use rustc_errors::Applicability;
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use rustc_hir::{GenericArg, HirId, Node, Path, TyKind};
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use rustc_hir::{GenericArg, HirId, Local, Node, Path, TyKind};
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use rustc_lint::LateContext;
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use rustc_middle::lint::in_external_macro;
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use rustc_middle::ty::Ty;
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@ -8,6 +8,27 @@ use clippy_utils::diagnostics::span_lint_and_sugg;
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use crate::transmute::MISSING_TRANSMUTE_ANNOTATIONS;
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fn get_parent_local_binding_ty<'tcx>(cx: &LateContext<'tcx>, expr_hir_id: HirId) -> Option<Local<'tcx>> {
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let mut parent_iter = cx.tcx.hir().parent_iter(expr_hir_id);
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if let Some((_, node)) = parent_iter.next() {
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match node {
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Node::Local(local) => Some(*local),
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Node::Block(_) => {
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if let Some((parent_hir_id, Node::Expr(expr))) = parent_iter.next()
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&& matches!(expr.kind, rustc_hir::ExprKind::Block(_, _))
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{
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get_parent_local_binding_ty(cx, parent_hir_id)
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} else {
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None
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}
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},
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_ => None,
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}
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} else {
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None
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}
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}
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pub(super) fn check<'tcx>(
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cx: &LateContext<'tcx>,
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path: &Path<'tcx>,
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@ -33,12 +54,14 @@ pub(super) fn check<'tcx>(
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return false;
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}
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// If it's being set as a local variable value...
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if let Some((_, node)) = cx.tcx.hir().parent_iter(expr_hir_id).next()
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&& let Node::Local(local) = node
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if let Some(local) = get_parent_local_binding_ty(cx, expr_hir_id)
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// ... which does have type annotations.
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&& local.ty.is_some()
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&& let Some(ty) = local.ty
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{
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return false;
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// If this is a `let x: _ =`, we shouldn't lint.
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if !matches!(ty.kind, TyKind::Infer) {
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return false;
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}
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}
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span_lint_and_sugg(
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cx,
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@ -1,6 +1,7 @@
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//@aux-build:macro_rules.rs
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#![warn(clippy::missing_transmute_annotations)]
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#![allow(clippy::let_with_type_underscore)]
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#[macro_use]
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extern crate macro_rules;
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@ -68,7 +69,12 @@ unsafe fn foo9() -> i32 {
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}
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fn main() {
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let x: _ = unsafe { std::mem::transmute::<[u16; 2], i32>([1u16, 2u16]) };
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//~^ ERROR: transmute used without annotations
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unsafe {
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let x: _ = std::mem::transmute::<[u16; 2], i32>([1u16, 2u16]);
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//~^ ERROR: transmute used without annotations
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// Should not warn.
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std::mem::transmute::<[u16; 2], i32>([1u16, 2u16]);
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let x = std::mem::transmute::<[u16; 2], i32>([1u16, 2u16]);
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@ -76,4 +82,5 @@ fn main() {
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let x: i32 = std::mem::transmute::<_, i32>([1u16, 2u16]);
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let x: i32 = std::mem::transmute([1u16, 2u16]);
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}
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let x: i32 = unsafe { std::mem::transmute([1u16, 2u16]) };
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}
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@ -1,6 +1,7 @@
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//@aux-build:macro_rules.rs
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#![warn(clippy::missing_transmute_annotations)]
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#![allow(clippy::let_with_type_underscore)]
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#[macro_use]
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extern crate macro_rules;
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@ -68,7 +69,12 @@ unsafe fn foo9() -> i32 {
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}
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fn main() {
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let x: _ = unsafe { std::mem::transmute::<_, i32>([1u16, 2u16]) };
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//~^ ERROR: transmute used without annotations
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unsafe {
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let x: _ = std::mem::transmute::<_, i32>([1u16, 2u16]);
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//~^ ERROR: transmute used without annotations
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// Should not warn.
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std::mem::transmute::<[u16; 2], i32>([1u16, 2u16]);
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let x = std::mem::transmute::<[u16; 2], i32>([1u16, 2u16]);
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@ -76,4 +82,5 @@ fn main() {
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let x: i32 = std::mem::transmute::<_, i32>([1u16, 2u16]);
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let x: i32 = std::mem::transmute([1u16, 2u16]);
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}
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let x: i32 = unsafe { std::mem::transmute([1u16, 2u16]) };
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}
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@ -1,5 +1,5 @@
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error: transmute used without annotations
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--> tests/ui/missing_transmute_annotations.rs:19:15
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--> tests/ui/missing_transmute_annotations.rs:20:15
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LL | std::mem::transmute([1u16, 2u16])
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| ^^^^^^^^^ help: consider adding missing annotations: `transmute::<[u16; 2], i32>`
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@ -8,37 +8,37 @@ LL | std::mem::transmute([1u16, 2u16])
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= help: to override `-D warnings` add `#[allow(clippy::missing_transmute_annotations)]`
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error: transmute used without annotations
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--> tests/ui/missing_transmute_annotations.rs:24:15
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--> tests/ui/missing_transmute_annotations.rs:25:15
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LL | std::mem::transmute::<_, _>([1u16, 2u16])
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| ^^^^^^^^^^^^^^^^^ help: consider adding missing annotations: `transmute::<[u16; 2], i32>`
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error: transmute used without annotations
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--> tests/ui/missing_transmute_annotations.rs:29:15
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--> tests/ui/missing_transmute_annotations.rs:30:15
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LL | std::mem::transmute::<_, i32>([1u16, 2u16])
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| ^^^^^^^^^^^^^^^^^^^ help: consider adding missing annotations: `transmute::<[u16; 2], i32>`
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error: transmute used without annotations
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--> tests/ui/missing_transmute_annotations.rs:34:15
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--> tests/ui/missing_transmute_annotations.rs:35:15
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LL | std::mem::transmute::<[u16; 2], _>([1u16, 2u16])
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| ^^^^^^^^^^^^^^^^^^^^^^^^ help: consider adding missing annotations: `transmute::<[u16; 2], i32>`
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error: transmute used without annotations
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--> tests/ui/missing_transmute_annotations.rs:39:32
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--> tests/ui/missing_transmute_annotations.rs:40:32
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LL | let x: i32 = bar(std::mem::transmute::<[u16; 2], _>([1u16, 2u16]));
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| ^^^^^^^^^^^^^^^^^^^^^^^^ help: consider adding missing annotations: `transmute::<[u16; 2], i32>`
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error: transmute used without annotations
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--> tests/ui/missing_transmute_annotations.rs:41:19
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--> tests/ui/missing_transmute_annotations.rs:42:19
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LL | bar(std::mem::transmute::<[u16; 2], _>([1u16, 2u16]))
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| ^^^^^^^^^^^^^^^^^^^^^^^^ help: consider adding missing annotations: `transmute::<[u16; 2], i32>`
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error: transmute used without annotations
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--> tests/ui/missing_transmute_annotations.rs:10:19
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--> tests/ui/missing_transmute_annotations.rs:11:19
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LL | std::mem::transmute($e)
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| ^^^^^^^^^ help: consider adding missing annotations: `transmute::<[u16; 2], i32>`
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@ -49,16 +49,28 @@ LL | local_bad_transmute!([1u16, 2u16])
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= note: this error originates in the macro `local_bad_transmute` (in Nightly builds, run with -Z macro-backtrace for more info)
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error: transmute used without annotations
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--> tests/ui/missing_transmute_annotations.rs:61:15
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--> tests/ui/missing_transmute_annotations.rs:62:15
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LL | std::mem::transmute(0i32)
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| ^^^^^^^^^ help: consider adding missing annotations: `transmute::<i32, Foo>`
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error: transmute used without annotations
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--> tests/ui/missing_transmute_annotations.rs:66:15
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--> tests/ui/missing_transmute_annotations.rs:67:15
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LL | std::mem::transmute(Foo::A)
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| ^^^^^^^^^ help: consider adding missing annotations: `transmute::<Foo, i32>`
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error: aborting due to 9 previous errors
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error: transmute used without annotations
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--> tests/ui/missing_transmute_annotations.rs:72:35
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LL | let x: _ = unsafe { std::mem::transmute::<_, i32>([1u16, 2u16]) };
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| ^^^^^^^^^^^^^^^^^^^ help: consider adding missing annotations: `transmute::<[u16; 2], i32>`
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error: transmute used without annotations
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--> tests/ui/missing_transmute_annotations.rs:75:30
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LL | let x: _ = std::mem::transmute::<_, i32>([1u16, 2u16]);
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| ^^^^^^^^^^^^^^^^^^^ help: consider adding missing annotations: `transmute::<[u16; 2], i32>`
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error: aborting due to 11 previous errors
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