Remove no longer used contract_checks intrinsic

The contract_checks compiler flag is now used to determine
if runtime contract checks should be enabled, as opposed
to the compiler intrinsic as previously.

Author: dawidl022

compiler/rustc_hir/src/lang_items.rs

@@ -429,7 +429,6 @@ language_item_table! {
     // Experimental lang items for implementing contract pre- and post-condition checking.
     ContractBuildCheckEnsures, sym::contract_build_check_ensures, contract_build_check_ensures_fn, Target::Fn, GenericRequirement::None;
     ContractCheckRequires,     sym::contract_check_requires,      contract_check_requires_fn,      Target::Fn, GenericRequirement::None;
-    ContractChecks,            sym::contract_checks,              contract_checks_fn,              Target::Fn, GenericRequirement::None;
 
     // Experimental lang items for `MCP: Low level components for async drop`(https://github.com/rust-lang/compiler-team/issues/727)
     DefaultTrait4,           sym::default_trait4,      default_trait4_trait,       Target::Trait,          GenericRequirement::None;

compiler/rustc_hir_analysis/src/check/intrinsic.rs

@@ -647,8 +647,6 @@ pub(crate) fn check_intrinsic_type(
 
         sym::box_new => (1, 0, vec![param(0)], Ty::new_box(tcx, param(0))),
 
-        // contract_checks() -> bool
-        sym::contract_checks => (0, 0, Vec::new(), tcx.types.bool),
         // contract_check_requires::<C>(C) -> bool, where C: impl Fn() -> bool
         sym::contract_check_requires => (1, 0, vec![param(0)], tcx.types.unit),
         sym::contract_check_ensures => {

compiler/rustc_mir_transform/src/lower_intrinsics.rs

@@ -34,17 +34,6 @@ impl<'tcx> crate::MirPass<'tcx> for LowerIntrinsics {
                         ));
                         terminator.kind = TerminatorKind::Goto { target };
                     }
-                    sym::contract_checks => {
-                        let target = target.unwrap();
-                        block.statements.push(Statement::new(
-                            terminator.source_info,
-                            StatementKind::Assign(Box::new((
-                                *destination,
-                                Rvalue::NullaryOp(NullOp::ContractChecks, tcx.types.bool),
-                            ))),
-                        ));
-                        terminator.kind = TerminatorKind::Goto { target };
-                    }
                     sym::forget => {
                         let target = target.unwrap();
                         block.statements.push(Statement::new(

library/core/src/intrinsics/mod.rs

@@ -2631,24 +2631,6 @@ pub const unsafe fn const_make_global(ptr: *mut u8) -> *const u8 {
     ptr
 }
 
-/// Returns whether we should perform contract-checking at runtime.
-///
-/// This is meant to be similar to the ub_checks intrinsic, in terms
-/// of not prematurely committing at compile-time to whether contract
-/// checking is turned on, so that we can specify contracts in libstd
-/// and let an end user opt into turning them on.
-#[unstable(feature = "contracts_internals", issue = "128044" /* compiler-team#759 */)]
-#[rustc_const_unstable(feature = "contracts", issue = "128044")]
-#[inline(always)]
-#[lang = "contract_checks"]
-#[rustc_intrinsic]
-pub const fn contract_checks() -> bool {
-    // FIXME: should this be `false` or `cfg!(contract_checks)`?
-
-    // cfg!(contract_checks)
-    false
-}
-
 /// Check if the pre-condition `cond` has been met.
 ///
 /// By default, if `contract_checks` is enabled, this will panic with no unwind if the condition

tests/ui/contracts/internal_machinery/contract-intrinsics.rs

@@ -1,36 +1,23 @@
-//@ revisions: default unchk_pass chk_pass chk_fail_ensures chk_fail_requires
+//@ revisions: default chk_fail_ensures chk_fail_requires
 //
 //@ [default] run-pass
-//@ [unchk_pass] run-pass
-//@ [chk_pass] run-pass
 //@ [chk_fail_requires] run-crash
 //@ [chk_fail_ensures] run-crash
-//
-//@ [unchk_pass] compile-flags: -Zcontract-checks=no
-//@ [chk_pass] compile-flags: -Zcontract-checks=yes
-//@ [chk_fail_requires] compile-flags: -Zcontract-checks=yes
-//@ [chk_fail_ensures] compile-flags: -Zcontract-checks=yes
-#![feature(cfg_contract_checks, contracts_internals, core_intrinsics)]
+#![feature(contracts_internals, core_intrinsics)]
 
 fn main() {
-    #[cfg(any(default, unchk_pass))] // default: disabled
-    assert_eq!(core::intrinsics::contract_checks(), false);
-
-    #[cfg(chk_pass)] // explicitly enabled
-    assert_eq!(core::intrinsics::contract_checks(), true);
-
     // always pass
     core::intrinsics::contract_check_requires(|| true);
 
     // always fail
-    #[cfg(any(chk_fail_requires))]
+    #[cfg(chk_fail_requires)]
     core::intrinsics::contract_check_requires(|| false);
 
     let doubles_to_two = { let old = 2; move |ret: &u32 | ret + ret == old };
     // Always pass
     core::intrinsics::contract_check_ensures(Some(doubles_to_two), 1);
 
     // always fail
-    #[cfg(any(chk_fail_ensures))]
+    #[cfg(chk_fail_ensures)]
     core::intrinsics::contract_check_ensures(Some(doubles_to_two), 2);
 }

tests/ui/contracts/internal_machinery/contract-lang-items.chk_fail_post.stderr

@@ -1,5 +1,5 @@
 warning: the feature `contracts` is incomplete and may not be safe to use and/or cause compiler crashes
-  --> $DIR/contract-lang-items.rs:15:12
+  --> $DIR/contract-lang-items.rs:8:12
    |
 LL | #![feature(contracts)] // to access core::contracts
    |            ^^^^^^^^^

tests/ui/contracts/internal_machinery/contract-lang-items.chk_pass.stderr

@@ -1,5 +1,5 @@
 warning: the feature `contracts` is incomplete and may not be safe to use and/or cause compiler crashes
-  --> $DIR/contract-lang-items.rs:15:12
+  --> $DIR/contract-lang-items.rs:8:12
    |
 LL | #![feature(contracts)] // to access core::contracts
    |            ^^^^^^^^^

tests/ui/contracts/internal_machinery/contract-lang-items.rs

@@ -1,27 +1,16 @@
-//@ revisions: unchk_pass unchk_fail_post chk_pass chk_fail_post
+//@ revisions: unchk_pass chk_pass chk_fail_post
 //
 //@ [unchk_pass] run-pass
-//@ [unchk_fail_post] run-pass
 //@ [chk_pass] run-pass
 //
 //@ [chk_fail_post] run-crash
-//
-//@ [unchk_pass] compile-flags: -Zcontract-checks=no
-//@ [unchk_fail_post] compile-flags: -Zcontract-checks=no
-//
-//@ [chk_pass] compile-flags: -Zcontract-checks=yes
-//@ [chk_fail_post] compile-flags: -Zcontract-checks=yes
 
 #![feature(contracts)] // to access core::contracts
 //~^ WARN the feature `contracts` is incomplete and may not be safe to use and/or cause compiler crashes [incomplete_features]
 #![feature(contracts_internals)] // to access check_requires lang item
 #![feature(core_intrinsics)]
 fn foo(x: Baz) -> i32 {
-    let injected_checker = if core::intrinsics::contract_checks() {
-        Some(core::contracts::build_check_ensures(|ret| *ret > 100))
-    } else {
-        None
-    };
+    let injected_checker =  Some(core::contracts::build_check_ensures(|ret| *ret > 100));
 
     let ret = x.baz + 50;
     core::intrinsics::contract_check_ensures(injected_checker, ret)
@@ -31,11 +20,11 @@ struct Baz { baz: i32 }
 
 
 const BAZ_PASS_PRE_POST: Baz = Baz { baz: 100 };
-#[cfg(any(unchk_fail_post, chk_fail_post))]
+#[cfg(chk_fail_post)]
 const BAZ_FAIL_POST: Baz = Baz { baz: 10 };
 
 fn main() {
     assert_eq!(foo(BAZ_PASS_PRE_POST), 150);
-    #[cfg(any(unchk_fail_post, chk_fail_post))]
+    #[cfg(chk_fail_post)]
     foo(BAZ_FAIL_POST);
 }

tests/ui/contracts/internal_machinery/contract-lang-items.unchk_pass.stderr

@@ -1,5 +1,5 @@
 warning: the feature `contracts` is incomplete and may not be safe to use and/or cause compiler crashes
-  --> $DIR/contract-lang-items.rs:15:12
+  --> $DIR/contract-lang-items.rs:8:12
    |
 LL | #![feature(contracts)] // to access core::contracts
    |            ^^^^^^^^^

tests/ui/contracts/internal_machinery/internal-feature-gating.rs

@@ -2,8 +2,6 @@
 
 fn main() {
     // intrinsics are guarded by contracts_internals feature gate.
-    core::intrinsics::contract_checks();
-    //~^ ERROR use of unstable library feature `contracts_internals`
     core::intrinsics::contract_check_requires(|| true);
     //~^ ERROR use of unstable library feature `contracts_internals`
     core::intrinsics::contract_check_ensures(Some(|_: &&u32| true), &1);