Auto merge of #123322 - matthewjasper:remove-mir-unsafeck, r=lcnr,compiler-errors

Remove MIR unsafe check

Now that THIR unsafeck is enabled by default in stable I think we can remove MIR unsafeck entirely. This PR also removes safety information from MIR.

5 files changed, 1 insertions, 85 deletions

diff --git a/compiler/rustc_middle/src/arena.rs b/compiler/rustc_middle/src/arena.rs
index c90427256b8..bd11b3eb04c 100644
--- a/compiler/rustc_middle/src/arena.rs
+++ b/compiler/rustc_middle/src/arena.rs
@@ -35,7 +35,6 @@ macro_rules! arena_types {
             )>,
             [] crate_for_resolver: rustc_data_structures::steal::Steal<(rustc_ast::Crate, rustc_ast::AttrVec)>,
             [] resolutions: rustc_middle::ty::ResolverGlobalCtxt,
-            [decode] unsafety_check_result: rustc_middle::mir::UnsafetyCheckResult,
             [decode] code_region: rustc_middle::mir::coverage::CodeRegion,
             [] const_allocs: rustc_middle::mir::interpret::Allocation,
             [] region_scope_tree: rustc_middle::middle::region::ScopeTree,
diff --git a/compiler/rustc_middle/src/mir/mod.rs b/compiler/rustc_middle/src/mir/mod.rs
index e5a650c5ac4..b87e9ee60be 100644
--- a/compiler/rustc_middle/src/mir/mod.rs
+++ b/compiler/rustc_middle/src/mir/mod.rs
@@ -845,17 +845,6 @@ impl<'tcx> Body<'tcx> {
     }
 }
 
-#[derive(Copy, Clone, PartialEq, Eq, Debug, TyEncodable, TyDecodable, HashStable)]
-pub enum Safety {
-    Safe,
-    /// Unsafe because of compiler-generated unsafe code, like `await` desugaring
-    BuiltinUnsafe,
-    /// Unsafe because of an unsafe fn
-    FnUnsafe,
-    /// Unsafe because of an `unsafe` block
-    ExplicitUnsafe(hir::HirId),
-}
-
 impl<'tcx> Index<BasicBlock> for Body<'tcx> {
     type Output = BasicBlockData<'tcx>;
 
@@ -1611,8 +1600,6 @@ pub struct SourceScopeData<'tcx> {
 pub struct SourceScopeLocalData {
     /// An `HirId` with lint levels equivalent to this scope's lint levels.
     pub lint_root: hir::HirId,
-    /// The unsafe block that contains this node.
-    pub safety: Safety,
 }
 
 /// A collection of projections into user types.
@@ -1888,7 +1875,7 @@ mod size_asserts {
     // tidy-alphabetical-start
     static_assert_size!(BasicBlockData<'_>, 144);
     static_assert_size!(LocalDecl<'_>, 40);
-    static_assert_size!(SourceScopeData<'_>, 72);
+    static_assert_size!(SourceScopeData<'_>, 64);
     static_assert_size!(Statement<'_>, 32);
     static_assert_size!(StatementKind<'_>, 16);
     static_assert_size!(Terminator<'_>, 112);
diff --git a/compiler/rustc_middle/src/mir/query.rs b/compiler/rustc_middle/src/mir/query.rs
index 731e050ca9b..d286c208083 100644
--- a/compiler/rustc_middle/src/mir/query.rs
+++ b/compiler/rustc_middle/src/mir/query.rs
@@ -3,9 +3,7 @@
 use crate::mir;
 use crate::ty::{self, OpaqueHiddenType, Ty, TyCtxt};
 use rustc_data_structures::fx::FxIndexMap;
-use rustc_data_structures::unord::UnordSet;
 use rustc_errors::ErrorGuaranteed;
-use rustc_hir as hir;
 use rustc_hir::def_id::LocalDefId;
 use rustc_index::bit_set::BitMatrix;
 use rustc_index::{Idx, IndexVec};
@@ -18,67 +16,6 @@ use std::fmt::{self, Debug};
 
 use super::{ConstValue, SourceInfo};
 
-#[derive(Copy, Clone, PartialEq, TyEncodable, TyDecodable, HashStable, Debug)]
-pub enum UnsafetyViolationKind {
-    /// Unsafe operation outside `unsafe`.
-    General,
-    /// Unsafe operation in an `unsafe fn` but outside an `unsafe` block.
-    /// Has to be handled as a lint for backwards compatibility.
-    UnsafeFn,
-}
-
-#[derive(Clone, PartialEq, TyEncodable, TyDecodable, HashStable, Debug)]
-pub enum UnsafetyViolationDetails {
-    CallToUnsafeFunction,
-    UseOfInlineAssembly,
-    InitializingTypeWith,
-    CastOfPointerToInt,
-    UseOfMutableStatic,
-    UseOfExternStatic,
-    DerefOfRawPointer,
-    AccessToUnionField,
-    MutationOfLayoutConstrainedField,
-    BorrowOfLayoutConstrainedField,
-    CallToFunctionWith {
-        /// Target features enabled in callee's `#[target_feature]` but missing in
-        /// caller's `#[target_feature]`.
-        missing: Vec<Symbol>,
-        /// Target features in `missing` that are enabled at compile time
-        /// (e.g., with `-C target-feature`).
-        build_enabled: Vec<Symbol>,
-    },
-}
-
-#[derive(Clone, PartialEq, TyEncodable, TyDecodable, HashStable, Debug)]
-pub struct UnsafetyViolation {
-    pub source_info: SourceInfo,
-    pub lint_root: hir::HirId,
-    pub kind: UnsafetyViolationKind,
-    pub details: UnsafetyViolationDetails,
-}
-
-#[derive(Copy, Clone, PartialEq, TyEncodable, TyDecodable, HashStable, Debug)]
-pub enum UnusedUnsafe {
-    /// `unsafe` block contains no unsafe operations
-    /// > ``unnecessary `unsafe` block``
-    Unused,
-    /// `unsafe` block nested under another (used) `unsafe` block
-    /// > ``… because it's nested under this `unsafe` block``
-    InUnsafeBlock(hir::HirId),
-}
-
-#[derive(TyEncodable, TyDecodable, HashStable, Debug)]
-pub struct UnsafetyCheckResult {
-    /// Violations that are propagated *upwards* from this function.
-    pub violations: Vec<UnsafetyViolation>,
-
-    /// Used `unsafe` blocks in this function. This is used for the "unused_unsafe" lint.
-    pub used_unsafe_blocks: UnordSet<hir::HirId>,
-
-    /// This is `Some` iff the item is not a closure.
-    pub unused_unsafes: Option<Vec<(hir::HirId, UnusedUnsafe)>>,
-}
-
 rustc_index::newtype_index! {
     #[derive(HashStable)]
     #[encodable]
diff --git a/compiler/rustc_middle/src/query/mod.rs b/compiler/rustc_middle/src/query/mod.rs
index 5e4454db3e2..62a60a650ec 100644
--- a/compiler/rustc_middle/src/query/mod.rs
+++ b/compiler/rustc_middle/src/query/mod.rs
@@ -877,12 +877,6 @@ rustc_queries! {
         desc { |tcx| "collecting all inherent impls for `{:?}`", key }
     }
 
-    /// The result of unsafety-checking this `LocalDefId` with the old checker.
-    query mir_unsafety_check_result(key: LocalDefId) -> &'tcx mir::UnsafetyCheckResult {
-        desc { |tcx| "unsafety-checking `{}`", tcx.def_path_str(key) }
-        cache_on_disk_if { true }
-    }
-
     /// Unsafety-check this `LocalDefId`.
     query check_unsafety(key: LocalDefId) {
         desc { |tcx| "unsafety-checking `{}`", tcx.def_path_str(key) }
diff --git a/compiler/rustc_middle/src/ty/codec.rs b/compiler/rustc_middle/src/ty/codec.rs
index ddbc0bffaed..e7a1679b151 100644
--- a/compiler/rustc_middle/src/ty/codec.rs
+++ b/compiler/rustc_middle/src/ty/codec.rs
@@ -458,7 +458,6 @@ impl_decodable_via_ref! {
     &'tcx ty::List<ty::PolyExistentialPredicate<'tcx>>,
     &'tcx traits::ImplSource<'tcx, ()>,
     &'tcx mir::Body<'tcx>,
-    &'tcx mir::UnsafetyCheckResult,
     &'tcx mir::BorrowCheckResult<'tcx>,
     &'tcx mir::coverage::CodeRegion,
     &'tcx ty::List<ty::BoundVariableKind>,