Normalize instance substs during legacy symbol mangling

compiler/rustc_symbol_mangling/src/legacy.rs

@@ -51,16 +51,22 @@ pub(super) fn mangle<'tcx>(
     // Erase regions because they may not be deterministic when hashed
     // and should not matter anyhow.
     let instance_ty = tcx.erase_regions(instance_ty);
+    // Also normalize the instance's substs, because we want to make
+    // sure that  we're fully evaluating any unevaluated consts that
+    // leak into this mangled name.
+    // FIXME(compiler-errors): Ideally, like the equivalent call in the
+    // v1 mangling shceme, this should not be needed.
+    let substs = tcx.normalize_erasing_regions(ty::ParamEnv::reveal_all(), instance.substs);
 
-    let hash = get_symbol_hash(tcx, instance, instance_ty, instantiating_crate);
+    let hash = get_symbol_hash(tcx, instance.def, substs, instance_ty, instantiating_crate);
 
     let mut printer = SymbolPrinter { tcx, path: SymbolPath::new(), keep_within_component: false };
     printer
         .print_def_path(
             def_id,
             if let ty::InstanceDef::DropGlue(_, _) = instance.def {
                 // Add the name of the dropped type to the symbol name
-                &*instance.substs
+                &*substs
             } else {
                 &[]
             },
@@ -82,7 +88,8 @@ fn get_symbol_hash<'tcx>(
     tcx: TyCtxt<'tcx>,
 
     // instance this name will be for
-    instance: Instance<'tcx>,
+    instance: ty::InstanceDef<'tcx>,
+    substs: ty::SubstsRef<'tcx>,
 
     // type of the item, without any generic
     // parameters substituted; this is
@@ -93,7 +100,6 @@ fn get_symbol_hash<'tcx>(
     instantiating_crate: Option<CrateNum>,
 ) -> u64 {
     let def_id = instance.def_id();
-    let substs = instance.substs;
     debug!("get_symbol_hash(def_id={:?}, parameters={:?})", def_id, substs);
 
     tcx.with_stable_hashing_context(|mut hcx| {
@@ -131,7 +137,7 @@ fn get_symbol_hash<'tcx>(
                 // We want to avoid accidental collision between different types of instances.
                 // Especially, `VTableShim`s and `ReifyShim`s may overlap with their original
                 // instances without this.
-                discriminant(&instance.def).hash_stable(hcx, &mut hasher);
+                discriminant(&instance).hash_stable(hcx, &mut hasher);
             });
         });
 

src/test/ui/const-generics/generic_const_exprs/issue-100217.rs

@@ -0,0 +1,42 @@
+// build-pass
+
+#![allow(incomplete_features)]
+#![feature(generic_const_exprs)]
+
+trait TraitOne {
+    const MY_NUM: usize;
+    type MyErr: std::fmt::Debug;
+
+    fn do_one_stuff(arr: [u8; Self::MY_NUM]) -> Result<(), Self::MyErr>;
+}
+
+trait TraitTwo {
+    fn do_two_stuff();
+}
+
+impl<O: TraitOne> TraitTwo for O
+where
+    [(); Self::MY_NUM]:,
+{
+    fn do_two_stuff() {
+        O::do_one_stuff([5; Self::MY_NUM]).unwrap()
+    }
+}
+
+struct Blargotron;
+
+#[derive(Debug)]
+struct ErrTy<const N: usize>([(); N]);
+
+impl TraitOne for Blargotron {
+    const MY_NUM: usize = 3;
+    type MyErr = ErrTy<{ Self::MY_NUM }>;
+
+    fn do_one_stuff(_arr: [u8; Self::MY_NUM]) -> Result<(), Self::MyErr> {
+        Ok(())
+    }
+}
+
+fn main() {
+    Blargotron::do_two_stuff();
+}

src/test/ui/const-generics/generic_const_exprs/issue-73298.rs

@@ -0,0 +1,23 @@
+// build-pass
+
+#![allow(incomplete_features)]
+#![feature(generic_const_exprs)]
+
+use std::convert::AsMut;
+use std::default::Default;
+
+trait Foo: Sized {
+    type Baz: Default + AsMut<[u8]>;
+    fn bar() {
+        Self::Baz::default().as_mut();
+    }
+}
+
+impl Foo for () {
+    type Baz = [u8; 1 * 1];
+    //type Baz = [u8; 1];
+}
+
+fn main() {
+    <() as Foo>::bar();
+}

src/test/ui/const-generics/generic_const_exprs/issue-82268.rs

@@ -0,0 +1,73 @@
+// build-pass
+
+#![allow(incomplete_features)]
+#![feature(generic_const_exprs)]
+
+trait Collate<Op> {
+    type Pass;
+    type Fail;
+
+    fn collate(self) -> (Self::Pass, Self::Fail);
+}
+
+impl<Op> Collate<Op> for () {
+    type Pass = ();
+    type Fail = ();
+
+    fn collate(self) -> ((), ()) {
+        ((), ())
+    }
+}
+
+trait CollateStep<X, Prev> {
+    type Pass;
+    type Fail;
+    fn collate_step(x: X, prev: Prev) -> (Self::Pass, Self::Fail);
+}
+
+impl<X, P, F> CollateStep<X, (P, F)> for () {
+    type Pass = (X, P);
+    type Fail = F;
+
+    fn collate_step(x: X, (p, f): (P, F)) -> ((X, P), F) {
+        ((x, p), f)
+    }
+}
+
+struct CollateOpImpl<const MASK: u32>;
+trait CollateOpStep {
+    type NextOp;
+    type Apply;
+}
+
+impl<const MASK: u32> CollateOpStep for CollateOpImpl<MASK>
+where
+    CollateOpImpl<{ MASK >> 1 }>: Sized,
+{
+    type NextOp = CollateOpImpl<{ MASK >> 1 }>;
+    type Apply = ();
+}
+
+impl<H, T, Op: CollateOpStep> Collate<Op> for (H, T)
+where
+    T: Collate<Op::NextOp>,
+    Op::Apply: CollateStep<H, (T::Pass, T::Fail)>,
+{
+    type Pass = <Op::Apply as CollateStep<H, (T::Pass, T::Fail)>>::Pass;
+    type Fail = <Op::Apply as CollateStep<H, (T::Pass, T::Fail)>>::Fail;
+
+    fn collate(self) -> (Self::Pass, Self::Fail) {
+        <Op::Apply as CollateStep<H, (T::Pass, T::Fail)>>::collate_step(self.0, self.1.collate())
+    }
+}
+
+fn collate<X, const MASK: u32>(x: X) -> (X::Pass, X::Fail)
+where
+    X: Collate<CollateOpImpl<MASK>>,
+{
+    x.collate()
+}
+
+fn main() {
+    dbg!(collate::<_, 5>(("Hello", (42, ('!', ())))));
+}

src/test/ui/const-generics/generic_const_exprs/issue-83972.rs

@@ -0,0 +1,38 @@
+// build-pass
+
+#![allow(incomplete_features)]
+#![feature(generic_const_exprs)]
+
+pub trait Foo {
+    fn foo(&self);
+}
+
+pub struct FooImpl<const N: usize>;
+impl<const N: usize> Foo for FooImpl<N> {
+    fn foo(&self) {}
+}
+
+pub trait Bar: 'static {
+    type Foo: Foo;
+    fn get() -> &'static Self::Foo;
+}
+
+struct BarImpl;
+impl Bar for BarImpl {
+    type Foo = FooImpl<
+        {
+            { 4 }
+        },
+    >;
+    fn get() -> &'static Self::Foo {
+        &FooImpl
+    }
+}
+
+pub fn boom<B: Bar>() {
+    B::get().foo();
+}
+
+fn main() {
+    boom::<BarImpl>();
+}

src/test/ui/const-generics/generic_const_exprs/issue-84669.rs

@@ -0,0 +1,30 @@
+// build-pass
+
+#![feature(generic_const_exprs)]
+#![allow(incomplete_features)]
+
+trait Foo {
+    type Output;
+
+    fn foo() -> Self::Output;
+}
+
+impl Foo for [u8; 3] {
+    type Output = [u8; 1 + 2];
+
+    fn foo() -> [u8; 3] {
+        [1u8; 3]
+    }
+}
+
+fn bug<const N: usize>()
+where
+    [u8; N]: Foo,
+    <[u8; N] as Foo>::Output: AsRef<[u8]>,
+{
+    <[u8; N]>::foo().as_ref();
+}
+
+fn main() {
+    bug::<3>();
+}

src/test/ui/const-generics/generic_const_exprs/issue-86710.rs

@@ -0,0 +1,73 @@
+// build-pass
+
+#![allow(incomplete_features)]
+#![feature(generic_const_exprs)]
+
+use std::marker::PhantomData;
+
+fn main() {
+    let x = FooImpl::<BarImpl<1>> { phantom: PhantomData };
+    let _ = x.foo::<BarImpl<1>>();
+}
+
+trait Foo<T>
+where
+    T: Bar,
+{
+    fn foo<U>(&self)
+    where
+        T: Operation<U>,
+        <T as Operation<U>>::Output: Bar;
+}
+
+struct FooImpl<T>
+where
+    T: Bar,
+{
+    phantom: PhantomData<T>,
+}
+
+impl<T> Foo<T> for FooImpl<T>
+where
+    T: Bar,
+{
+    fn foo<U>(&self)
+    where
+        T: Operation<U>,
+        <T as Operation<U>>::Output: Bar,
+    {
+        <<T as Operation<U>>::Output as Bar>::error_occurs_here();
+    }
+}
+
+trait Bar {
+    fn error_occurs_here();
+}
+
+struct BarImpl<const N: usize>;
+
+impl<const N: usize> Bar for BarImpl<N> {
+    fn error_occurs_here() {}
+}
+
+trait Operation<Rhs> {
+    type Output;
+}
+
+//// Part-A: This causes error.
+impl<const M: usize, const N: usize> Operation<BarImpl<M>> for BarImpl<N>
+where
+    BarImpl<{ N + M }>: Sized,
+{
+    type Output = BarImpl<{ N + M }>;
+}
+
+//// Part-B: This doesn't cause error.
+// impl<const M: usize, const N: usize> Operation<BarImpl<M>> for BarImpl<N> {
+//     type Output = BarImpl<M>;
+// }
+
+//// Part-C: This also doesn't cause error.
+// impl<const M: usize, const N: usize> Operation<BarImpl<M>> for BarImpl<N> {
+//     type Output = BarImpl<{ M }>;
+// }