New upstream version 1.57.0+dfsg1

[rustc.git] / compiler / rustc_mir / src / const_eval / fn_queries.rs

diff --git a/compiler/rustc_mir/src/const_eval/fn_queries.rs b/compiler/rustc_mir/src/const_eval/fn_queries.rs
deleted file mode 100644 (file)
index 40419a4..0000000
--- a/compiler/rustc_mir/src/const_eval/fn_queries.rs
+++ /dev/null
@@ -1,112 +0,0 @@
-use rustc_hir as hir;
-use rustc_hir::def_id::{DefId, LocalDefId};
-use rustc_middle::hir::map::blocks::FnLikeNode;
-use rustc_middle::ty::query::Providers;
-use rustc_middle::ty::TyCtxt;
-use rustc_span::symbol::Symbol;
-use rustc_target::spec::abi::Abi;
-
-/// Whether the `def_id` counts as const fn in your current crate, considering all active
-/// feature gates
-pub fn is_const_fn(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
-    tcx.is_const_fn_raw(def_id)
-        && match is_unstable_const_fn(tcx, def_id) {
-            Some(feature_name) => {
-                // has a `rustc_const_unstable` attribute, check whether the user enabled the
-                // corresponding feature gate.
-                tcx.features().declared_lib_features.iter().any(|&(sym, _)| sym == feature_name)
-            }
-            // functions without const stability are either stable user written
-            // const fn or the user is using feature gates and we thus don't
-            // care what they do
-            None => true,
-        }
-}
-
-/// Whether the `def_id` is an unstable const fn and what feature gate is necessary to enable it
-pub fn is_unstable_const_fn(tcx: TyCtxt<'_>, def_id: DefId) -> Option<Symbol> {
-    if tcx.is_const_fn_raw(def_id) {
-        let const_stab = tcx.lookup_const_stability(def_id)?;
-        if const_stab.level.is_unstable() { Some(const_stab.feature) } else { None }
-    } else {
-        None
-    }
-}
-
-pub fn is_parent_const_impl_raw(tcx: TyCtxt<'_>, hir_id: hir::HirId) -> bool {
-    let parent_id = tcx.hir().get_parent_did(hir_id);
-    if !parent_id.is_top_level_module() { is_const_impl_raw(tcx, parent_id) } else { false }
-}
-
-/// Checks whether the function has a `const` modifier or, in case it is an intrinsic, whether
-/// said intrinsic has a `rustc_const_{un,}stable` attribute.
-fn is_const_fn_raw(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
-    let hir_id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local());
-
-    let node = tcx.hir().get(hir_id);
-
-    if let hir::Node::ForeignItem(hir::ForeignItem { kind: hir::ForeignItemKind::Fn(..), .. }) =
-        node
-    {
-        // Intrinsics use `rustc_const_{un,}stable` attributes to indicate constness. All other
-        // foreign items cannot be evaluated at compile-time.
-        if let Abi::RustIntrinsic | Abi::PlatformIntrinsic = tcx.hir().get_foreign_abi(hir_id) {
-            tcx.lookup_const_stability(def_id).is_some()
-        } else {
-            false
-        }
-    } else if let Some(fn_like) = FnLikeNode::from_node(node) {
-        if fn_like.constness() == hir::Constness::Const {
-            return true;
-        }
-
-        // If the function itself is not annotated with `const`, it may still be a `const fn`
-        // if it resides in a const trait impl.
-        is_parent_const_impl_raw(tcx, hir_id)
-    } else if let hir::Node::Ctor(_) = node {
-        true
-    } else {
-        false
-    }
-}
-
-/// Checks whether the given item is an `impl` that has a `const` modifier.
-fn is_const_impl_raw(tcx: TyCtxt<'_>, def_id: LocalDefId) -> bool {
-    let hir_id = tcx.hir().local_def_id_to_hir_id(def_id);
-    let node = tcx.hir().get(hir_id);
-    matches!(
-        node,
-        hir::Node::Item(hir::Item {
-            kind: hir::ItemKind::Impl(hir::Impl { constness: hir::Constness::Const, .. }),
-            ..
-        })
-    )
-}
-
-fn is_promotable_const_fn(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
-    is_const_fn(tcx, def_id)
-        && match tcx.lookup_const_stability(def_id) {
-            Some(stab) => {
-                if cfg!(debug_assertions) && stab.promotable {
-                    let sig = tcx.fn_sig(def_id);
-                    assert_eq!(
-                        sig.unsafety(),
-                        hir::Unsafety::Normal,
-                        "don't mark const unsafe fns as promotable",
-                        // https://github.com/rust-lang/rust/pull/53851#issuecomment-418760682
-                    );
-                }
-                stab.promotable
-            }
-            None => false,
-        }
-}
-
-pub fn provide(providers: &mut Providers) {
-    *providers = Providers {
-        is_const_fn_raw,
-        is_const_impl_raw: |tcx, def_id| is_const_impl_raw(tcx, def_id.expect_local()),
-        is_promotable_const_fn,
-        ..*providers
-    };
-}