Auto merge of rust-lang#70848 - Mark-Simulacrum:beta-next, r=Mark-Simulacrum

[beta] backports

* Use TypeRelating for instantiating query responses rust-lang#69591
* Move rustc-guide submodule to rustc-dev-guide rust-lang#69898

Author: bors

.gitmodules

@@ -31,9 +31,9 @@
 [submodule "src/stdarch"]
 	path = src/stdarch
 	url = https://github.com/rust-lang/stdarch.git
-[submodule "src/doc/rustc-guide"]
-	path = src/doc/rustc-guide
-	url = https://github.com/rust-lang/rustc-guide.git
+[submodule "src/doc/rustc-dev-guide"]
+	path = src/doc/rustc-dev-guide
+	url = https://github.com/rust-lang/rustc-dev-guide.git
 [submodule "src/doc/edition-guide"]
 	path = src/doc/edition-guide
 	url = https://github.com/rust-lang/edition-guide.git

rustfmt.toml

@@ -20,7 +20,7 @@ ignore = [
     "src/doc/nomicon",
     "src/doc/reference",
     "src/doc/rust-by-example",
-    "src/doc/rustc-guide",
+    "src/doc/rustc-dev-guide",
     "src/llvm-project",
     "src/stdarch",
     "src/tools/cargo",

src/bootstrap/test.rs

@@ -1493,22 +1493,22 @@ impl Step for RustcGuide {
     const ONLY_HOSTS: bool = true;
 
     fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
-        run.path("src/doc/rustc-guide")
+        run.path("src/doc/rustc-dev-guide")
     }
 
     fn make_run(run: RunConfig<'_>) {
         run.builder.ensure(RustcGuide);
     }
 
     fn run(self, builder: &Builder<'_>) {
-        let src = builder.src.join("src/doc/rustc-guide");
+        let src = builder.src.join("src/doc/rustc-dev-guide");
         let mut rustbook_cmd = builder.tool_cmd(Tool::Rustbook);
         let toolstate = if try_run(builder, rustbook_cmd.arg("linkcheck").arg(&src)) {
             ToolState::TestPass
         } else {
             ToolState::TestFail
         };
-        builder.save_toolstate("rustc-guide", toolstate);
+        builder.save_toolstate("rustc-dev-guide", toolstate);
     }
 }
 

src/bootstrap/toolstate.rs

@@ -89,7 +89,7 @@ static STABLE_TOOLS: &[(&str, &str)] = &[
 static NIGHTLY_TOOLS: &[(&str, &str)] = &[
     ("miri", "src/tools/miri"),
     ("embedded-book", "src/doc/embedded-book"),
-    ("rustc-guide", "src/doc/rustc-guide"),
+    ("rustc-dev-guide", "src/doc/rustc-dev-guide"),
 ];
 
 fn print_error(tool: &str, submodule: &str) {

src/ci/docker/x86_64-gnu-tools/checktools.sh

@@ -14,7 +14,7 @@ python2.7 "$X_PY" test --no-fail-fast \
     src/doc/rust-by-example \
     src/doc/embedded-book \
     src/doc/edition-guide \
-    src/doc/rustc-guide \
+    src/doc/rustc-dev-guide \
     src/tools/clippy \
     src/tools/rls \
     src/tools/rustfmt \

src/doc/rustc-dev-guide

@@ -12,14 +12,15 @@ use crate::infer::canonical::{
     Canonical, CanonicalVarValues, CanonicalizedQueryResponse, Certainty, OriginalQueryValues,
     QueryOutlivesConstraint, QueryRegionConstraints, QueryResponse,
 };
+use crate::infer::nll_relate::{NormalizationStrategy, TypeRelating, TypeRelatingDelegate};
 use crate::infer::region_constraints::{Constraint, RegionConstraintData};
-use crate::infer::InferCtxtBuilder;
-use crate::infer::{InferCtxt, InferOk, InferResult};
+use crate::infer::{InferCtxt, InferCtxtBuilder, InferOk, InferResult, NLLRegionVariableOrigin};
 use crate::traits::query::{Fallible, NoSolution};
-use crate::traits::TraitEngine;
+use crate::traits::{DomainGoal, TraitEngine};
 use crate::traits::{Obligation, ObligationCause, PredicateObligation};
 use rustc::arena::ArenaAllocatable;
 use rustc::ty::fold::TypeFoldable;
+use rustc::ty::relate::TypeRelation;
 use rustc::ty::subst::{GenericArg, GenericArgKind};
 use rustc::ty::{self, BoundVar, Ty, TyCtxt};
 use rustc_data_structures::captures::Captures;
@@ -304,13 +305,31 @@ impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
                 }
 
                 (GenericArgKind::Type(v1), GenericArgKind::Type(v2)) => {
-                    let ok = self.at(cause, param_env).eq(v1, v2)?;
-                    obligations.extend(ok.into_obligations());
+                    TypeRelating::new(
+                        self,
+                        QueryTypeRelatingDelegate {
+                            infcx: self,
+                            param_env,
+                            cause,
+                            obligations: &mut obligations,
+                        },
+                        ty::Variance::Invariant,
+                    )
+                    .relate(&v1, &v2)?;
                 }
 
                 (GenericArgKind::Const(v1), GenericArgKind::Const(v2)) => {
-                    let ok = self.at(cause, param_env).eq(v1, v2)?;
-                    obligations.extend(ok.into_obligations());
+                    TypeRelating::new(
+                        self,
+                        QueryTypeRelatingDelegate {
+                            infcx: self,
+                            param_env,
+                            cause,
+                            obligations: &mut obligations,
+                        },
+                        ty::Variance::Invariant,
+                    )
+                    .relate(&v1, &v2)?;
                 }
 
                 _ => {
@@ -656,3 +675,55 @@ pub fn make_query_region_constraints<'tcx>(
 
     QueryRegionConstraints { outlives, member_constraints: member_constraints.clone() }
 }
+
+struct QueryTypeRelatingDelegate<'a, 'tcx> {
+    infcx: &'a InferCtxt<'a, 'tcx>,
+    obligations: &'a mut Vec<PredicateObligation<'tcx>>,
+    param_env: ty::ParamEnv<'tcx>,
+    cause: &'a ObligationCause<'tcx>,
+}
+
+impl<'tcx> TypeRelatingDelegate<'tcx> for QueryTypeRelatingDelegate<'_, 'tcx> {
+    fn create_next_universe(&mut self) -> ty::UniverseIndex {
+        self.infcx.create_next_universe()
+    }
+
+    fn next_existential_region_var(&mut self, from_forall: bool) -> ty::Region<'tcx> {
+        let origin = NLLRegionVariableOrigin::Existential { from_forall };
+        self.infcx.next_nll_region_var(origin)
+    }
+
+    fn next_placeholder_region(&mut self, placeholder: ty::PlaceholderRegion) -> ty::Region<'tcx> {
+        self.infcx.tcx.mk_region(ty::RePlaceholder(placeholder))
+    }
+
+    fn generalize_existential(&mut self, universe: ty::UniverseIndex) -> ty::Region<'tcx> {
+        self.infcx.next_nll_region_var_in_universe(
+            NLLRegionVariableOrigin::Existential { from_forall: false },
+            universe,
+        )
+    }
+
+    fn push_outlives(&mut self, sup: ty::Region<'tcx>, sub: ty::Region<'tcx>) {
+        self.obligations.push(Obligation {
+            cause: self.cause.clone(),
+            param_env: self.param_env,
+            predicate: ty::Predicate::RegionOutlives(ty::Binder::dummy(ty::OutlivesPredicate(
+                sup, sub,
+            ))),
+            recursion_depth: 0,
+        });
+    }
+
+    fn push_domain_goal(&mut self, _: DomainGoal<'tcx>) {
+        bug!("should never be invoked with eager normalization")
+    }
+
+    fn normalization() -> NormalizationStrategy {
+        NormalizationStrategy::Eager
+    }
+
+    fn forbid_inference_vars() -> bool {
+        true
+    }
+}

src/doc/rustc-guide

@@ -0,0 +1,33 @@
+// Regression test for issue #69490
+
+// check-pass
+
+pub trait Trait<T> {
+    const S: &'static str;
+}
+
+impl<T> Trait<()> for T
+where
+    T: for<'a> Trait<&'a ()>,
+{
+    // Use of `T::S` here caused an ICE
+    const S: &'static str = T::S;
+}
+
+// Some similar cases that didn't ICE:
+
+impl<'a, T> Trait<()> for (T,)
+where
+    T: Trait<&'a ()>,
+{
+    const S: &'static str = T::S;
+}
+
+impl<T> Trait<()> for [T; 1]
+where
+    T: Trait<for<'a> fn(&'a ())>,
+{
+    const S: &'static str = T::S;
+}
+
+fn main() {}

src/librustc_infer/infer/canonical/query_response.rs

@@ -41,7 +41,7 @@
         'ryankurte', 'thejpster', 'therealprof',
     },
     'edition-guide': {'ehuss', 'Centril', 'steveklabnik'},
-    'rustc-guide': {'mark-i-m', 'spastorino', 'amanjeev', 'JohnTitor'},
+    'rustc-dev-guide': {'mark-i-m', 'spastorino', 'amanjeev', 'JohnTitor'},
 }
 
 REPOS = {
@@ -55,7 +55,7 @@
     'rust-by-example': 'https://github.com/rust-lang/rust-by-example',
     'embedded-book': 'https://github.com/rust-embedded/book',
     'edition-guide': 'https://github.com/rust-lang/edition-guide',
-    'rustc-guide': 'https://github.com/rust-lang/rustc-guide',
+    'rustc-dev-guide': 'https://github.com/rust-lang/rustc-dev-guide',
 }
 
 
@@ -204,7 +204,7 @@ def update_latest(
                 old = status[os]
                 new = s.get(tool, old)
                 status[os] = new
-                maintainers = ' '.join('@'+name for name in MAINTAINERS[tool])
+                maintainers = ' '.join('@'+name for name in MAINTAINERS.get(tool, ()))
                 # comparing the strings, but they are ordered appropriately:
                 # "test-pass" > "test-fail" > "build-fail"
                 if new > old: