#![allow(clippy::module_name_repetitions)]
+use core::ops::ControlFlow;
use rustc_ast::ast::Mutability;
-use rustc_data_structures::fx::FxHashMap;
+use rustc_data_structures::fx::{FxHashMap, FxHashSet};
use rustc_hir as hir;
+use rustc_hir::def::{CtorKind, CtorOf, DefKind, Res};
use rustc_hir::def_id::DefId;
-use rustc_hir::{TyKind, Unsafety};
+use rustc_hir::{Expr, FnDecl, LangItem, TyKind, Unsafety};
use rustc_infer::infer::TyCtxtInferExt;
use rustc_lint::LateContext;
-use rustc_middle::ty::subst::{GenericArg, GenericArgKind};
-use rustc_middle::ty::{self, AdtDef, IntTy, Ty, TypeFoldable, UintTy};
-use rustc_span::sym;
-use rustc_span::symbol::{Ident, Symbol};
-use rustc_span::DUMMY_SP;
+use rustc_middle::mir::interpret::{ConstValue, Scalar};
+use rustc_middle::ty::{GenericArg, GenericArgKind};
+use rustc_middle::ty::{
+ self, AdtDef, Binder, BoundRegion, DefIdTree, FnSig, IntTy, ParamEnv, Predicate, PredicateKind, ProjectionTy,
+ Region, RegionKind, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable, TypeVisitor, UintTy, VariantDef, VariantDiscr,
+};
+use rustc_span::symbol::Ident;
+use rustc_span::{sym, Span, Symbol, DUMMY_SP};
+use rustc_target::abi::{Size, VariantIdx};
+use rustc_trait_selection::infer::InferCtxtExt;
use rustc_trait_selection::traits::query::normalize::AtExt;
+use std::iter;
-use crate::{match_def_path, must_use_attr};
+use crate::{match_def_path, path_res, paths};
+// Checks if the given type implements copy.
pub fn is_copy<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
ty.is_copy_modulo_regions(cx.tcx.at(DUMMY_SP), cx.param_env)
}
/// Checks whether a type can be partially moved.
-pub fn can_partially_move_ty(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
+pub fn can_partially_move_ty<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
if has_drop(cx, ty) || is_copy(cx, ty) {
return false;
}
}
}
-/// Walks into `ty` and returns `true` if any inner type is the same as `other_ty`
-pub fn contains_ty(ty: Ty<'_>, other_ty: Ty<'_>) -> bool {
- ty.walk().any(|inner| match inner.unpack() {
- GenericArgKind::Type(inner_ty) => ty::TyS::same_type(other_ty, inner_ty),
- GenericArgKind::Lifetime(_) | GenericArgKind::Const(_) => false,
- })
-}
-
/// Walks into `ty` and returns `true` if any inner type is an instance of the given adt
/// constructor.
-pub fn contains_adt_constructor(ty: Ty<'_>, adt: &AdtDef) -> bool {
+pub fn contains_adt_constructor<'tcx>(ty: Ty<'tcx>, adt: AdtDef<'tcx>) -> bool {
ty.walk().any(|inner| match inner.unpack() {
GenericArgKind::Type(inner_ty) => inner_ty.ty_adt_def() == Some(adt),
GenericArgKind::Lifetime(_) | GenericArgKind::Const(_) => false,
pub fn get_iterator_item_ty<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> Option<Ty<'tcx>> {
cx.tcx
.get_diagnostic_item(sym::Iterator)
- .and_then(|iter_did| {
- cx.tcx.associated_items(iter_did).find_by_name_and_kind(
- cx.tcx,
- Ident::from_str("Item"),
- ty::AssocKind::Type,
- iter_did,
- )
- })
- .map(|assoc| {
+ .and_then(|iter_did| get_associated_type(cx, ty, iter_did, "Item"))
+}
+
+/// Returns the associated type `name` for `ty` as an implementation of `trait_id`.
+/// Do not invoke without first verifying that the type implements the trait.
+pub fn get_associated_type<'tcx>(
+ cx: &LateContext<'tcx>,
+ ty: Ty<'tcx>,
+ trait_id: DefId,
+ name: &str,
+) -> Option<Ty<'tcx>> {
+ cx.tcx
+ .associated_items(trait_id)
+ .find_by_name_and_kind(cx.tcx, Ident::from_str(name), ty::AssocKind::Type, trait_id)
+ .and_then(|assoc| {
let proj = cx.tcx.mk_projection(assoc.def_id, cx.tcx.mk_substs_trait(ty, &[]));
- cx.tcx.normalize_erasing_regions(cx.param_env, proj)
+ cx.tcx.try_normalize_erasing_regions(cx.param_env, proj).ok()
})
}
+/// Get the diagnostic name of a type, e.g. `sym::HashMap`. To check if a type
+/// implements a trait marked with a diagnostic item use [`implements_trait`].
+///
+/// For a further exploitation what diagnostic items are see [diagnostic items] in
+/// rustc-dev-guide.
+///
+/// [Diagnostic Items]: https://rustc-dev-guide.rust-lang.org/diagnostics/diagnostic-items.html
+pub fn get_type_diagnostic_name(cx: &LateContext<'_>, ty: Ty<'_>) -> Option<Symbol> {
+ match ty.kind() {
+ ty::Adt(adt, _) => cx.tcx.get_diagnostic_name(adt.did()),
+ _ => None,
+ }
+}
+
/// Returns true if ty has `iter` or `iter_mut` methods
pub fn has_iter_method(cx: &LateContext<'_>, probably_ref_ty: Ty<'_>) -> Option<Symbol> {
// FIXME: instead of this hard-coded list, we should check if `<adt>::iter`
// exists and has the desired signature. Unfortunately FnCtxt is not exported
// so we can't use its `lookup_method` method.
let into_iter_collections: &[Symbol] = &[
- sym::vec_type,
- sym::option_type,
- sym::result_type,
+ sym::Vec,
+ sym::Option,
+ sym::Result,
sym::BTreeMap,
sym::BTreeSet,
- sym::vecdeque_type,
+ sym::VecDeque,
sym::LinkedList,
sym::BinaryHeap,
- sym::hashset_type,
- sym::hashmap_type,
+ sym::HashSet,
+ sym::HashMap,
sym::PathBuf,
sym::Path,
sym::Receiver,
];
let ty_to_check = match probably_ref_ty.kind() {
- ty::Ref(_, ty_to_check, _) => ty_to_check,
+ ty::Ref(_, ty_to_check, _) => *ty_to_check,
_ => probably_ref_ty,
};
let def_id = match ty_to_check.kind() {
ty::Array(..) => return Some(sym::array),
ty::Slice(..) => return Some(sym::slice),
- ty::Adt(adt, _) => adt.did,
+ ty::Adt(adt, _) => adt.did(),
_ => return None,
};
}
/// Checks whether a type implements a trait.
-/// See also `get_trait_def_id`.
+/// The function returns false in case the type contains an inference variable.
+///
+/// See:
+/// * [`get_trait_def_id`](super::get_trait_def_id) to get a trait [`DefId`].
+/// * [Common tools for writing lints] for an example how to use this function and other options.
+///
+/// [Common tools for writing lints]: https://github.com/rust-lang/rust-clippy/blob/master/book/src/development/common_tools_writing_lints.md#checking-if-a-type-implements-a-specific-trait
pub fn implements_trait<'tcx>(
cx: &LateContext<'tcx>,
ty: Ty<'tcx>,
trait_id: DefId,
ty_params: &[GenericArg<'tcx>],
) -> bool {
- // Do not check on infer_types to avoid panic in evaluate_obligation.
- if ty.has_infer_types() {
- return false;
- }
- let ty = cx.tcx.erase_regions(ty);
+ implements_trait_with_env(cx.tcx, cx.param_env, ty, trait_id, ty_params)
+}
+
+/// Same as `implements_trait` but allows using a `ParamEnv` different from the lint context.
+pub fn implements_trait_with_env<'tcx>(
+ tcx: TyCtxt<'tcx>,
+ param_env: ParamEnv<'tcx>,
+ ty: Ty<'tcx>,
+ trait_id: DefId,
+ ty_params: &[GenericArg<'tcx>],
+) -> bool {
+ // Clippy shouldn't have infer types
+ assert!(!ty.needs_infer());
+
+ let ty = tcx.erase_regions(ty);
if ty.has_escaping_bound_vars() {
return false;
}
- let ty_params = cx.tcx.mk_substs(ty_params.iter());
- cx.tcx
- .type_implements_trait((trait_id, ty, ty_params, cx.param_env))
- .must_apply_modulo_regions()
+ let ty_params = tcx.mk_substs(ty_params.iter());
+ tcx.infer_ctxt().enter(|infcx| {
+ infcx
+ .type_implements_trait(trait_id, ty, ty_params, param_env)
+ .must_apply_modulo_regions()
+ })
}
/// Checks whether this type implements `Drop`.
// Returns whether the type has #[must_use] attribute
pub fn is_must_use_ty<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
match ty.kind() {
- ty::Adt(adt, _) => must_use_attr(cx.tcx.get_attrs(adt.did)).is_some(),
- ty::Foreign(ref did) => must_use_attr(cx.tcx.get_attrs(*did)).is_some(),
- ty::Slice(ty)
- | ty::Array(ty, _)
- | ty::RawPtr(ty::TypeAndMut { ty, .. })
- | ty::Ref(_, ty, _) => {
+ ty::Adt(adt, _) => cx.tcx.has_attr(adt.did(), sym::must_use),
+ ty::Foreign(did) => cx.tcx.has_attr(*did, sym::must_use),
+ ty::Slice(ty) | ty::Array(ty, _) | ty::RawPtr(ty::TypeAndMut { ty, .. }) | ty::Ref(_, ty, _) => {
// for the Array case we don't need to care for the len == 0 case
// because we don't want to lint functions returning empty arrays
is_must_use_ty(cx, *ty)
- }
- ty::Tuple(substs) => substs.types().any(|ty| is_must_use_ty(cx, ty)),
- ty::Opaque(ref def_id, _) => {
+ },
+ ty::Tuple(substs) => substs.iter().any(|ty| is_must_use_ty(cx, ty)),
+ ty::Opaque(def_id, _) => {
for (predicate, _) in cx.tcx.explicit_item_bounds(*def_id) {
- if let ty::PredicateKind::Trait(trait_predicate, _) = predicate.kind().skip_binder()
- {
- if must_use_attr(cx.tcx.get_attrs(trait_predicate.trait_ref.def_id)).is_some() {
+ if let ty::PredicateKind::Trait(trait_predicate) = predicate.kind().skip_binder() {
+ if cx.tcx.has_attr(trait_predicate.trait_ref.def_id, sym::must_use) {
return true;
}
}
}
false
- }
- ty::Dynamic(binder, _) => {
+ },
+ ty::Dynamic(binder, _, _) => {
for predicate in binder.iter() {
if let ty::ExistentialPredicate::Trait(ref trait_ref) = predicate.skip_binder() {
- if must_use_attr(cx.tcx.get_attrs(trait_ref.def_id)).is_some() {
+ if cx.tcx.has_attr(trait_ref.def_id, sym::must_use) {
return true;
}
}
}
false
- }
+ },
_ => false,
}
}
// FIXME: Per https://doc.rust-lang.org/nightly/nightly-rustc/rustc_trait_selection/infer/at/struct.At.html#method.normalize
-// this function can be removed once the `normalizie` method does not panic when normalization does
+// this function can be removed once the `normalize` method does not panic when normalization does
// not succeed
/// Checks if `Ty` is normalizable. This function is useful
/// to avoid crashes on `layout_of`.
-pub fn is_normalizable<'tcx>(
- cx: &LateContext<'tcx>,
- param_env: ty::ParamEnv<'tcx>,
- ty: Ty<'tcx>,
-) -> bool {
+pub fn is_normalizable<'tcx>(cx: &LateContext<'tcx>, param_env: ty::ParamEnv<'tcx>, ty: Ty<'tcx>) -> bool {
is_normalizable_helper(cx, param_env, ty, &mut FxHashMap::default())
}
ty: Ty<'tcx>,
cache: &mut FxHashMap<Ty<'tcx>, bool>,
) -> bool {
- if let Some(&cached_result) = cache.get(ty) {
+ if let Some(&cached_result) = cache.get(&ty) {
return cached_result;
}
// prevent recursive loops, false-negative is better than endless loop leading to stack overflow
let cause = rustc_middle::traits::ObligationCause::dummy();
if infcx.at(&cause, param_env).normalize(ty).is_ok() {
match ty.kind() {
- ty::Adt(def, substs) => def.variants.iter().all(|variant| {
- variant.fields.iter().all(|field| {
- is_normalizable_helper(cx, param_env, field.ty(cx.tcx, substs), cache)
- })
+ ty::Adt(def, substs) => def.variants().iter().all(|variant| {
+ variant
+ .fields
+ .iter()
+ .all(|field| is_normalizable_helper(cx, param_env, field.ty(cx.tcx, substs), cache))
}),
_ => ty.walk().all(|generic_arg| match generic_arg.unpack() {
GenericArgKind::Type(inner_ty) if inner_ty != ty => {
is_normalizable_helper(cx, param_env, inner_ty, cache)
- }
+ },
_ => true, // if inner_ty == ty, we've already checked it
}),
}
result
}
-/// Returns true iff the given type is a primitive (a bool or char, any integer or floating-point
-/// number type, a str, or an array, slice, or tuple of those types).
+/// Returns `true` if the given type is a non aggregate primitive (a `bool` or `char`, any
+/// integer or floating-point number type). For checking aggregation of primitive types (e.g.
+/// tuples and slices of primitive type) see `is_recursively_primitive_type`
+pub fn is_non_aggregate_primitive_type(ty: Ty<'_>) -> bool {
+ matches!(ty.kind(), ty::Bool | ty::Char | ty::Int(_) | ty::Uint(_) | ty::Float(_))
+}
+
+/// Returns `true` if the given type is a primitive (a `bool` or `char`, any integer or
+/// floating-point number type, a `str`, or an array, slice, or tuple of those types).
pub fn is_recursively_primitive_type(ty: Ty<'_>) -> bool {
- match ty.kind() {
+ match *ty.kind() {
ty::Bool | ty::Char | ty::Int(_) | ty::Uint(_) | ty::Float(_) | ty::Str => true,
ty::Ref(_, inner, _) if *inner.kind() == ty::Str => true,
- ty::Array(inner_type, _) | ty::Slice(inner_type) => {
- is_recursively_primitive_type(inner_type)
- }
- ty::Tuple(inner_types) => inner_types.types().all(is_recursively_primitive_type),
+ ty::Array(inner_type, _) | ty::Slice(inner_type) => is_recursively_primitive_type(inner_type),
+ ty::Tuple(inner_types) => inner_types.iter().all(is_recursively_primitive_type),
_ => false,
}
}
-/// Checks if the type is equal to a diagnostic item
+/// Checks if the type is a reference equals to a diagnostic item
+pub fn is_type_ref_to_diagnostic_item(cx: &LateContext<'_>, ty: Ty<'_>, diag_item: Symbol) -> bool {
+ match ty.kind() {
+ ty::Ref(_, ref_ty, _) => match ref_ty.kind() {
+ ty::Adt(adt, _) => cx.tcx.is_diagnostic_item(diag_item, adt.did()),
+ _ => false,
+ },
+ _ => false,
+ }
+}
+
+/// Checks if the type is equal to a diagnostic item. To check if a type implements a
+/// trait marked with a diagnostic item use [`implements_trait`].
+///
+/// For a further exploitation what diagnostic items are see [diagnostic items] in
+/// rustc-dev-guide.
+///
+/// ---
///
/// If you change the signature, remember to update the internal lint `MatchTypeOnDiagItem`
+///
+/// [Diagnostic Items]: https://rustc-dev-guide.rust-lang.org/diagnostics/diagnostic-items.html
pub fn is_type_diagnostic_item(cx: &LateContext<'_>, ty: Ty<'_>, diag_item: Symbol) -> bool {
match ty.kind() {
- ty::Adt(adt, _) => cx.tcx.is_diagnostic_item(diag_item, adt.did),
+ ty::Adt(adt, _) => cx.tcx.is_diagnostic_item(diag_item, adt.did()),
_ => false,
}
}
-/// Checks if the type is equal to a lang item
+/// Checks if the type is equal to a lang item.
+///
+/// Returns `false` if the `LangItem` is not defined.
pub fn is_type_lang_item(cx: &LateContext<'_>, ty: Ty<'_>, lang_item: hir::LangItem) -> bool {
match ty.kind() {
- ty::Adt(adt, _) => cx.tcx.lang_items().require(lang_item).unwrap() == adt.did,
+ ty::Adt(adt, _) => cx
+ .tcx
+ .lang_items()
+ .require(lang_item)
+ .map_or(false, |li| li == adt.did()),
_ => false,
}
}
/// If you change the signature, remember to update the internal lint `MatchTypeOnDiagItem`
pub fn match_type(cx: &LateContext<'_>, ty: Ty<'_>, path: &[&str]) -> bool {
match ty.kind() {
- ty::Adt(adt, _) => match_def_path(cx, adt.did, path),
+ ty::Adt(adt, _) => match_def_path(cx, adt.did(), path),
_ => false,
}
}
+/// Checks if the drop order for a type matters. Some std types implement drop solely to
+/// deallocate memory. For these types, and composites containing them, changing the drop order
+/// won't result in any observable side effects.
+pub fn needs_ordered_drop<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
+ fn needs_ordered_drop_inner<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>, seen: &mut FxHashSet<Ty<'tcx>>) -> bool {
+ if !seen.insert(ty) {
+ return false;
+ }
+ if !ty.has_significant_drop(cx.tcx, cx.param_env) {
+ false
+ }
+ // Check for std types which implement drop, but only for memory allocation.
+ else if is_type_lang_item(cx, ty, LangItem::OwnedBox)
+ || matches!(
+ get_type_diagnostic_name(cx, ty),
+ Some(sym::HashSet | sym::Rc | sym::Arc | sym::cstring_type)
+ )
+ || match_type(cx, ty, &paths::WEAK_RC)
+ || match_type(cx, ty, &paths::WEAK_ARC)
+ {
+ // Check all of the generic arguments.
+ if let ty::Adt(_, subs) = ty.kind() {
+ subs.types().any(|ty| needs_ordered_drop_inner(cx, ty, seen))
+ } else {
+ true
+ }
+ } else if !cx
+ .tcx
+ .lang_items()
+ .drop_trait()
+ .map_or(false, |id| implements_trait(cx, ty, id, &[]))
+ {
+ // This type doesn't implement drop, so no side effects here.
+ // Check if any component type has any.
+ match ty.kind() {
+ ty::Tuple(fields) => fields.iter().any(|ty| needs_ordered_drop_inner(cx, ty, seen)),
+ ty::Array(ty, _) => needs_ordered_drop_inner(cx, *ty, seen),
+ ty::Adt(adt, subs) => adt
+ .all_fields()
+ .map(|f| f.ty(cx.tcx, subs))
+ .any(|ty| needs_ordered_drop_inner(cx, ty, seen)),
+ _ => true,
+ }
+ } else {
+ true
+ }
+ }
+
+ needs_ordered_drop_inner(cx, ty, &mut FxHashSet::default())
+}
+
/// Peels off all references on the type. Returns the underlying type and the number of references
/// removed.
pub fn peel_mid_ty_refs(ty: Ty<'_>) -> (Ty<'_>, usize) {
fn peel(ty: Ty<'_>, count: usize) -> (Ty<'_>, usize) {
- if let ty::Ref(_, ty, _) = ty.kind() { peel(ty, count + 1) } else { (ty, count) }
+ if let ty::Ref(_, ty, _) = ty.kind() {
+ peel(*ty, count + 1)
+ } else {
+ (ty, count)
+ }
}
peel(ty, 0)
}
-/// Peels off all references on the type.Returns the underlying type, the number of references
+/// Peels off all references on the type. Returns the underlying type, the number of references
/// removed, and whether the pointer is ultimately mutable or not.
pub fn peel_mid_ty_refs_is_mutable(ty: Ty<'_>) -> (Ty<'_>, usize, Mutability) {
fn f(ty: Ty<'_>, count: usize, mutability: Mutability) -> (Ty<'_>, usize, Mutability) {
match ty.kind() {
- ty::Ref(_, ty, Mutability::Mut) => f(ty, count + 1, mutability),
- ty::Ref(_, ty, Mutability::Not) => f(ty, count + 1, Mutability::Not),
+ ty::Ref(_, ty, Mutability::Mut) => f(*ty, count + 1, mutability),
+ ty::Ref(_, ty, Mutability::Not) => f(*ty, count + 1, Mutability::Not),
_ => (ty, count, mutability),
}
}
pub fn walk_ptrs_ty_depth(ty: Ty<'_>) -> (Ty<'_>, usize) {
fn inner(ty: Ty<'_>, depth: usize) -> (Ty<'_>, usize) {
match ty.kind() {
- ty::Ref(_, ty, _) => inner(ty, depth + 1),
+ ty::Ref(_, ty, _) => inner(*ty, depth + 1),
_ => (ty, depth),
}
}
/// Returns `true` if types `a` and `b` are same types having same `Const` generic args,
/// otherwise returns `false`
-pub fn same_type_and_consts(a: Ty<'tcx>, b: Ty<'tcx>) -> bool {
+pub fn same_type_and_consts<'tcx>(a: Ty<'tcx>, b: Ty<'tcx>) -> bool {
match (&a.kind(), &b.kind()) {
(&ty::Adt(did_a, substs_a), &ty::Adt(did_b, substs_b)) => {
if did_a != did_b {
return false;
}
- substs_a.iter().zip(substs_b.iter()).all(|(arg_a, arg_b)| {
- match (arg_a.unpack(), arg_b.unpack()) {
- (GenericArgKind::Const(inner_a), GenericArgKind::Const(inner_b)) => {
- inner_a == inner_b
- }
+ substs_a
+ .iter()
+ .zip(substs_b.iter())
+ .all(|(arg_a, arg_b)| match (arg_a.unpack(), arg_b.unpack()) {
+ (GenericArgKind::Const(inner_a), GenericArgKind::Const(inner_b)) => inner_a == inner_b,
(GenericArgKind::Type(type_a), GenericArgKind::Type(type_b)) => {
same_type_and_consts(type_a, type_b)
- }
+ },
_ => true,
+ })
+ },
+ _ => a == b,
+ }
+}
+
+/// Checks if a given type looks safe to be uninitialized.
+pub fn is_uninit_value_valid_for_ty(cx: &LateContext<'_>, ty: Ty<'_>) -> bool {
+ match *ty.kind() {
+ ty::Array(component, _) => is_uninit_value_valid_for_ty(cx, component),
+ ty::Tuple(types) => types.iter().all(|ty| is_uninit_value_valid_for_ty(cx, ty)),
+ ty::Adt(adt, _) => cx.tcx.lang_items().maybe_uninit() == Some(adt.did()),
+ _ => false,
+ }
+}
+
+/// Gets an iterator over all predicates which apply to the given item.
+pub fn all_predicates_of(tcx: TyCtxt<'_>, id: DefId) -> impl Iterator<Item = &(Predicate<'_>, Span)> {
+ let mut next_id = Some(id);
+ iter::from_fn(move || {
+ next_id.take().map(|id| {
+ let preds = tcx.predicates_of(id);
+ next_id = preds.parent;
+ preds.predicates.iter()
+ })
+ })
+ .flatten()
+}
+
+/// A signature for a function like type.
+#[derive(Clone, Copy)]
+pub enum ExprFnSig<'tcx> {
+ Sig(Binder<'tcx, FnSig<'tcx>>, Option<DefId>),
+ Closure(Option<&'tcx FnDecl<'tcx>>, Binder<'tcx, FnSig<'tcx>>),
+ Trait(Binder<'tcx, Ty<'tcx>>, Option<Binder<'tcx, Ty<'tcx>>>, Option<DefId>),
+}
+impl<'tcx> ExprFnSig<'tcx> {
+ /// Gets the argument type at the given offset. This will return `None` when the index is out of
+ /// bounds only for variadic functions, otherwise this will panic.
+ pub fn input(self, i: usize) -> Option<Binder<'tcx, Ty<'tcx>>> {
+ match self {
+ Self::Sig(sig, _) => {
+ if sig.c_variadic() {
+ sig.inputs().map_bound(|inputs| inputs.get(i).copied()).transpose()
+ } else {
+ Some(sig.input(i))
}
- })
+ },
+ Self::Closure(_, sig) => Some(sig.input(0).map_bound(|ty| ty.tuple_fields()[i])),
+ Self::Trait(inputs, _, _) => Some(inputs.map_bound(|ty| ty.tuple_fields()[i])),
}
- _ => a == b,
+ }
+
+ /// Gets the argument type at the given offset. For closures this will also get the type as
+ /// written. This will return `None` when the index is out of bounds only for variadic
+ /// functions, otherwise this will panic.
+ pub fn input_with_hir(self, i: usize) -> Option<(Option<&'tcx hir::Ty<'tcx>>, Binder<'tcx, Ty<'tcx>>)> {
+ match self {
+ Self::Sig(sig, _) => {
+ if sig.c_variadic() {
+ sig.inputs()
+ .map_bound(|inputs| inputs.get(i).copied())
+ .transpose()
+ .map(|arg| (None, arg))
+ } else {
+ Some((None, sig.input(i)))
+ }
+ },
+ Self::Closure(decl, sig) => Some((
+ decl.and_then(|decl| decl.inputs.get(i)),
+ sig.input(0).map_bound(|ty| ty.tuple_fields()[i]),
+ )),
+ Self::Trait(inputs, _, _) => Some((None, inputs.map_bound(|ty| ty.tuple_fields()[i]))),
+ }
+ }
+
+ /// Gets the result type, if one could be found. Note that the result type of a trait may not be
+ /// specified.
+ pub fn output(self) -> Option<Binder<'tcx, Ty<'tcx>>> {
+ match self {
+ Self::Sig(sig, _) | Self::Closure(_, sig) => Some(sig.output()),
+ Self::Trait(_, output, _) => output,
+ }
+ }
+
+ pub fn predicates_id(&self) -> Option<DefId> {
+ if let ExprFnSig::Sig(_, id) | ExprFnSig::Trait(_, _, id) = *self {
+ id
+ } else {
+ None
+ }
+ }
+}
+
+/// If the expression is function like, get the signature for it.
+pub fn expr_sig<'tcx>(cx: &LateContext<'tcx>, expr: &Expr<'_>) -> Option<ExprFnSig<'tcx>> {
+ if let Res::Def(DefKind::Fn | DefKind::Ctor(_, CtorKind::Fn) | DefKind::AssocFn, id) = path_res(cx, expr) {
+ Some(ExprFnSig::Sig(cx.tcx.fn_sig(id), Some(id)))
+ } else {
+ ty_sig(cx, cx.typeck_results().expr_ty_adjusted(expr).peel_refs())
+ }
+}
+
+/// If the type is function like, get the signature for it.
+pub fn ty_sig<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> Option<ExprFnSig<'tcx>> {
+ if ty.is_box() {
+ return ty_sig(cx, ty.boxed_ty());
+ }
+ match *ty.kind() {
+ ty::Closure(id, subs) => {
+ let decl = id
+ .as_local()
+ .and_then(|id| cx.tcx.hir().fn_decl_by_hir_id(cx.tcx.hir().local_def_id_to_hir_id(id)));
+ Some(ExprFnSig::Closure(decl, subs.as_closure().sig()))
+ },
+ ty::FnDef(id, subs) => Some(ExprFnSig::Sig(cx.tcx.bound_fn_sig(id).subst(cx.tcx, subs), Some(id))),
+ ty::Opaque(id, _) => sig_from_bounds(cx, ty, cx.tcx.item_bounds(id), cx.tcx.opt_parent(id)),
+ ty::FnPtr(sig) => Some(ExprFnSig::Sig(sig, None)),
+ ty::Dynamic(bounds, _, _) => {
+ let lang_items = cx.tcx.lang_items();
+ match bounds.principal() {
+ Some(bound)
+ if Some(bound.def_id()) == lang_items.fn_trait()
+ || Some(bound.def_id()) == lang_items.fn_once_trait()
+ || Some(bound.def_id()) == lang_items.fn_mut_trait() =>
+ {
+ let output = bounds
+ .projection_bounds()
+ .find(|p| lang_items.fn_once_output().map_or(false, |id| id == p.item_def_id()))
+ .map(|p| p.map_bound(|p| p.term.ty().unwrap()));
+ Some(ExprFnSig::Trait(bound.map_bound(|b| b.substs.type_at(0)), output, None))
+ },
+ _ => None,
+ }
+ },
+ ty::Projection(proj) => match cx.tcx.try_normalize_erasing_regions(cx.param_env, ty) {
+ Ok(normalized_ty) if normalized_ty != ty => ty_sig(cx, normalized_ty),
+ _ => sig_for_projection(cx, proj).or_else(|| sig_from_bounds(cx, ty, cx.param_env.caller_bounds(), None)),
+ },
+ ty::Param(_) => sig_from_bounds(cx, ty, cx.param_env.caller_bounds(), None),
+ _ => None,
+ }
+}
+
+fn sig_from_bounds<'tcx>(
+ cx: &LateContext<'tcx>,
+ ty: Ty<'tcx>,
+ predicates: &'tcx [Predicate<'tcx>],
+ predicates_id: Option<DefId>,
+) -> Option<ExprFnSig<'tcx>> {
+ let mut inputs = None;
+ let mut output = None;
+ let lang_items = cx.tcx.lang_items();
+
+ for pred in predicates {
+ match pred.kind().skip_binder() {
+ PredicateKind::Trait(p)
+ if (lang_items.fn_trait() == Some(p.def_id())
+ || lang_items.fn_mut_trait() == Some(p.def_id())
+ || lang_items.fn_once_trait() == Some(p.def_id()))
+ && p.self_ty() == ty =>
+ {
+ let i = pred.kind().rebind(p.trait_ref.substs.type_at(1));
+ if inputs.map_or(false, |inputs| i != inputs) {
+ // Multiple different fn trait impls. Is this even allowed?
+ return None;
+ }
+ inputs = Some(i);
+ },
+ PredicateKind::Projection(p)
+ if Some(p.projection_ty.item_def_id) == lang_items.fn_once_output()
+ && p.projection_ty.self_ty() == ty =>
+ {
+ if output.is_some() {
+ // Multiple different fn trait impls. Is this even allowed?
+ return None;
+ }
+ output = Some(pred.kind().rebind(p.term.ty().unwrap()));
+ },
+ _ => (),
+ }
+ }
+
+ inputs.map(|ty| ExprFnSig::Trait(ty, output, predicates_id))
+}
+
+fn sig_for_projection<'tcx>(cx: &LateContext<'tcx>, ty: ProjectionTy<'tcx>) -> Option<ExprFnSig<'tcx>> {
+ let mut inputs = None;
+ let mut output = None;
+ let lang_items = cx.tcx.lang_items();
+
+ for pred in cx
+ .tcx
+ .bound_explicit_item_bounds(ty.item_def_id)
+ .transpose_iter()
+ .map(|x| x.map_bound(|(p, _)| p))
+ {
+ match pred.0.kind().skip_binder() {
+ PredicateKind::Trait(p)
+ if (lang_items.fn_trait() == Some(p.def_id())
+ || lang_items.fn_mut_trait() == Some(p.def_id())
+ || lang_items.fn_once_trait() == Some(p.def_id())) =>
+ {
+ let i = pred
+ .map_bound(|pred| pred.kind().rebind(p.trait_ref.substs.type_at(1)))
+ .subst(cx.tcx, ty.substs);
+
+ if inputs.map_or(false, |inputs| inputs != i) {
+ // Multiple different fn trait impls. Is this even allowed?
+ return None;
+ }
+ inputs = Some(i);
+ },
+ PredicateKind::Projection(p) if Some(p.projection_ty.item_def_id) == lang_items.fn_once_output() => {
+ if output.is_some() {
+ // Multiple different fn trait impls. Is this even allowed?
+ return None;
+ }
+ output = Some(
+ pred.map_bound(|pred| pred.kind().rebind(p.term.ty().unwrap()))
+ .subst(cx.tcx, ty.substs),
+ );
+ },
+ _ => (),
+ }
+ }
+
+ inputs.map(|ty| ExprFnSig::Trait(ty, output, None))
+}
+
+#[derive(Clone, Copy)]
+pub enum EnumValue {
+ Unsigned(u128),
+ Signed(i128),
+}
+impl core::ops::Add<u32> for EnumValue {
+ type Output = Self;
+ fn add(self, n: u32) -> Self::Output {
+ match self {
+ Self::Unsigned(x) => Self::Unsigned(x + u128::from(n)),
+ Self::Signed(x) => Self::Signed(x + i128::from(n)),
+ }
+ }
+}
+
+/// Attempts to read the given constant as though it were an an enum value.
+#[expect(clippy::cast_possible_truncation, clippy::cast_possible_wrap)]
+pub fn read_explicit_enum_value(tcx: TyCtxt<'_>, id: DefId) -> Option<EnumValue> {
+ if let Ok(ConstValue::Scalar(Scalar::Int(value))) = tcx.const_eval_poly(id) {
+ match tcx.type_of(id).kind() {
+ ty::Int(_) => Some(EnumValue::Signed(match value.size().bytes() {
+ 1 => i128::from(value.assert_bits(Size::from_bytes(1)) as u8 as i8),
+ 2 => i128::from(value.assert_bits(Size::from_bytes(2)) as u16 as i16),
+ 4 => i128::from(value.assert_bits(Size::from_bytes(4)) as u32 as i32),
+ 8 => i128::from(value.assert_bits(Size::from_bytes(8)) as u64 as i64),
+ 16 => value.assert_bits(Size::from_bytes(16)) as i128,
+ _ => return None,
+ })),
+ ty::Uint(_) => Some(EnumValue::Unsigned(match value.size().bytes() {
+ 1 => value.assert_bits(Size::from_bytes(1)),
+ 2 => value.assert_bits(Size::from_bytes(2)),
+ 4 => value.assert_bits(Size::from_bytes(4)),
+ 8 => value.assert_bits(Size::from_bytes(8)),
+ 16 => value.assert_bits(Size::from_bytes(16)),
+ _ => return None,
+ })),
+ _ => None,
+ }
+ } else {
+ None
+ }
+}
+
+/// Gets the value of the given variant.
+pub fn get_discriminant_value(tcx: TyCtxt<'_>, adt: AdtDef<'_>, i: VariantIdx) -> EnumValue {
+ let variant = &adt.variant(i);
+ match variant.discr {
+ VariantDiscr::Explicit(id) => read_explicit_enum_value(tcx, id).unwrap(),
+ VariantDiscr::Relative(x) => match adt.variant((i.as_usize() - x as usize).into()).discr {
+ VariantDiscr::Explicit(id) => read_explicit_enum_value(tcx, id).unwrap() + x,
+ VariantDiscr::Relative(_) => EnumValue::Unsigned(x.into()),
+ },
+ }
+}
+
+/// Check if the given type is either `core::ffi::c_void`, `std::os::raw::c_void`, or one of the
+/// platform specific `libc::<platform>::c_void` types in libc.
+pub fn is_c_void(cx: &LateContext<'_>, ty: Ty<'_>) -> bool {
+ if let ty::Adt(adt, _) = ty.kind()
+ && let &[krate, .., name] = &*cx.get_def_path(adt.did())
+ && let sym::libc | sym::core | sym::std = krate
+ && name.as_str() == "c_void"
+ {
+ true
+ } else {
+ false
+ }
+}
+
+pub fn for_each_top_level_late_bound_region<B>(
+ ty: Ty<'_>,
+ f: impl FnMut(BoundRegion) -> ControlFlow<B>,
+) -> ControlFlow<B> {
+ struct V<F> {
+ index: u32,
+ f: F,
+ }
+ impl<'tcx, B, F: FnMut(BoundRegion) -> ControlFlow<B>> TypeVisitor<'tcx> for V<F> {
+ type BreakTy = B;
+ fn visit_region(&mut self, r: Region<'tcx>) -> ControlFlow<Self::BreakTy> {
+ if let RegionKind::ReLateBound(idx, bound) = r.kind() && idx.as_u32() == self.index {
+ (self.f)(bound)
+ } else {
+ ControlFlow::Continue(())
+ }
+ }
+ fn visit_binder<T: TypeVisitable<'tcx>>(&mut self, t: &Binder<'tcx, T>) -> ControlFlow<Self::BreakTy> {
+ self.index += 1;
+ let res = t.super_visit_with(self);
+ self.index -= 1;
+ res
+ }
+ }
+ ty.visit_with(&mut V { index: 0, f })
+}
+
+/// Gets the struct or enum variant from the given `Res`
+pub fn variant_of_res<'tcx>(cx: &LateContext<'tcx>, res: Res) -> Option<&'tcx VariantDef> {
+ match res {
+ Res::Def(DefKind::Struct, id) => Some(cx.tcx.adt_def(id).non_enum_variant()),
+ Res::Def(DefKind::Variant, id) => Some(cx.tcx.adt_def(cx.tcx.parent(id)).variant_with_id(id)),
+ Res::Def(DefKind::Ctor(CtorOf::Struct, _), id) => Some(cx.tcx.adt_def(cx.tcx.parent(id)).non_enum_variant()),
+ Res::Def(DefKind::Ctor(CtorOf::Variant, _), id) => {
+ let var_id = cx.tcx.parent(id);
+ Some(cx.tcx.adt_def(cx.tcx.parent(var_id)).variant_with_id(var_id))
+ },
+ Res::SelfCtor(id) => Some(cx.tcx.type_of(id).ty_adt_def().unwrap().non_enum_variant()),
+ _ => None,
+ }
+}
+
+/// Checks if the type is a type parameter implementing `FnOnce`, but not `FnMut`.
+pub fn ty_is_fn_once_param<'tcx>(tcx: TyCtxt<'_>, ty: Ty<'tcx>, predicates: &'tcx [Predicate<'_>]) -> bool {
+ let ty::Param(ty) = *ty.kind() else {
+ return false;
+ };
+ let lang = tcx.lang_items();
+ let (Some(fn_once_id), Some(fn_mut_id), Some(fn_id))
+ = (lang.fn_once_trait(), lang.fn_mut_trait(), lang.fn_trait())
+ else {
+ return false;
+ };
+ predicates
+ .iter()
+ .try_fold(false, |found, p| {
+ if let PredicateKind::Trait(p) = p.kind().skip_binder()
+ && let ty::Param(self_ty) = p.trait_ref.self_ty().kind()
+ && ty.index == self_ty.index
+ {
+ // This should use `super_traits_of`, but that's a private function.
+ if p.trait_ref.def_id == fn_once_id {
+ return Some(true);
+ } else if p.trait_ref.def_id == fn_mut_id || p.trait_ref.def_id == fn_id {
+ return None;
+ }
+ }
+ Some(found)
+ })
+ .unwrap_or(false)
+}
+
+/// Comes up with an "at least" guesstimate for the type's size, not taking into
+/// account the layout of type parameters.
+pub fn approx_ty_size<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> u64 {
+ use rustc_middle::ty::layout::LayoutOf;
+ if !is_normalizable(cx, cx.param_env, ty) {
+ return 0;
+ }
+ match (cx.layout_of(ty).map(|layout| layout.size.bytes()), ty.kind()) {
+ (Ok(size), _) => size,
+ (Err(_), ty::Tuple(list)) => list.as_substs().types().map(|t| approx_ty_size(cx, t)).sum(),
+ (Err(_), ty::Array(t, n)) => {
+ n.try_eval_usize(cx.tcx, cx.param_env).unwrap_or_default() * approx_ty_size(cx, *t)
+ },
+ (Err(_), ty::Adt(def, subst)) if def.is_struct() => def
+ .variants()
+ .iter()
+ .map(|v| {
+ v.fields
+ .iter()
+ .map(|field| approx_ty_size(cx, field.ty(cx.tcx, subst)))
+ .sum::<u64>()
+ })
+ .sum(),
+ (Err(_), ty::Adt(def, subst)) if def.is_enum() => def
+ .variants()
+ .iter()
+ .map(|v| {
+ v.fields
+ .iter()
+ .map(|field| approx_ty_size(cx, field.ty(cx.tcx, subst)))
+ .sum::<u64>()
+ })
+ .max()
+ .unwrap_or_default(),
+ (Err(_), ty::Adt(def, subst)) if def.is_union() => def
+ .variants()
+ .iter()
+ .map(|v| {
+ v.fields
+ .iter()
+ .map(|field| approx_ty_size(cx, field.ty(cx.tcx, subst)))
+ .max()
+ .unwrap_or_default()
+ })
+ .max()
+ .unwrap_or_default(),
+ (Err(_), _) => 0,
}
}
projects / rust.git / blobdiff