uwu error message

Author: lcnr

compiler/rustc_const_eval/src/interpret/util.rs

@@ -13,7 +13,7 @@ where
     T: TypeVisitable<'tcx>,
 {
     debug!("ensure_monomorphic_enough: ty={:?}", ty);
-    if !ty.needs_subst() {
+    if !(ty.needs_subst() || ty.has_opaque_types())  {
         return Ok(());
     }
 
@@ -31,7 +31,7 @@ where
             }
 
             match *ty.kind() {
-                ty::Param(_) => ControlFlow::Break(FoundParam),
+                ty::Param(_) | ty::Opaque(..) => ControlFlow::Break(FoundParam),
                 ty::Closure(def_id, substs)
                 | ty::Generator(def_id, substs, ..)
                 | ty::FnDef(def_id, substs) => {

compiler/rustc_trait_selection/src/traits/const_evaluatable.rs

@@ -186,9 +186,9 @@ pub fn is_const_evaluatable<'cx, 'tcx>(
         let concrete = infcx.const_eval_resolve(param_env, uv.expand(), Some(span));
         match concrete {
             Err(ErrorHandled::TooGeneric) => {
-                Err(NotConstEvaluatable::Error(infcx.tcx.sess.delay_span_bug(
+                Err(NotConstEvaluatable::Error(infcx.tcx.sess.span_err(
                     span,
-                    format!("Missing value for constant, but no error reported?"),
+                    format!("unable to use constant with a hidden value in the type system"),
                 )))
             }
             Err(ErrorHandled::Linted) => {
@@ -237,11 +237,13 @@ pub fn is_const_evaluatable<'cx, 'tcx>(
 
             Err(ErrorHandled::TooGeneric) => Err(if uv.has_infer_types_or_consts() {
                 NotConstEvaluatable::MentionsInfer
-                } else if uv.has_param_types_or_consts() {
+            } else if uv.has_param_types_or_consts() {
                 NotConstEvaluatable::MentionsParam
             } else {
-                let guar = infcx.tcx.sess.delay_span_bug(span, format!("Missing value for constant, but no error reported?"));
-                NotConstEvaluatable::Error(guar)
+                NotConstEvaluatable::Error(infcx.tcx.sess.span_err(
+                    span,
+                    format!("unable to use constant with a hidden value in the type system"),
+                ))
             }),
             Err(ErrorHandled::Linted) => {
                 let reported =

src/test/ui/const-generics/generic_const_exprs/issue-76595.rs

@@ -14,4 +14,5 @@ fn test<T, const P: usize>() where Bool<{core::mem::size_of::<T>() > 4}>: True {
 fn main() {
     test::<2>();
     //~^ ERROR this function takes 2 generic arguments
+    //~| ERROR unable to use constant with a hidden value in the type system
 }

src/test/ui/const-generics/generic_const_exprs/issue-76595.stderr

@@ -16,6 +16,12 @@ help: add missing generic argument
 LL |     test::<2, P>();
    |             +++
 
-error: aborting due to previous error
+error: unable to use constant with a hidden value in the type system
+  --> $DIR/issue-76595.rs:15:5
+   |
+LL |     test::<2>();
+   |     ^^^^^^^^^
+
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0107`.

src/test/ui/const-generics/issues/issue-86530.rs

@@ -15,6 +15,7 @@ where
 fn unit_literals() {
     z(" ");
     //~^ ERROR: the trait bound `&str: X` is not satisfied
+    //~| ERROR: unable to use constant with a hidden value in the type system
 }
 
 fn main() {}

src/test/ui/const-generics/issues/issue-86530.stderr

@@ -1,3 +1,9 @@
+error: unable to use constant with a hidden value in the type system
+  --> $DIR/issue-86530.rs:16:5
+   |
+LL |     z(" ");
+   |     ^
+
 error[E0277]: the trait bound `&str: X` is not satisfied
   --> $DIR/issue-86530.rs:16:7
    |
@@ -15,6 +21,6 @@ LL | where
 LL |     T: X,
    |        ^ required by this bound in `z`
 
-error: aborting due to previous error
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0277`.

src/test/ui/const-generics/issues/issue-98629.rs

@@ -4,12 +4,13 @@ trait Trait {
     const N: usize;
 }
 
+// FIXME: We should mention that `N` is missing
 impl const Trait for i32 {}
-//~^ ERROR not all trait items implemented, missing: `N`
 
 fn f()
 where
     [(); <i32 as Trait>::N]:,
+    //~^ ERROR unable to use constant with a hidden value in the type system
 {}
 
 fn main() {}

src/test/ui/const-generics/issues/issue-98629.stderr

@@ -1,12 +1,8 @@
-error[E0046]: not all trait items implemented, missing: `N`
-  --> $DIR/issue-98629.rs:7:1
+error: unable to use constant with a hidden value in the type system
+  --> $DIR/issue-98629.rs:11:5
    |
-LL |     const N: usize;
-   |     -------------- `N` from trait
-...
-LL | impl const Trait for i32 {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^ missing `N` in implementation
+LL |     [(); <i32 as Trait>::N]:,
+   |     ^^^^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0046`.

src/test/ui/impl-trait/in-ctfe/array-len.rs

@@ -1,4 +1,4 @@
-// This previously compiled, but broke with #101478.
+// This previously compiled, but was intentionally changed in #101478.
 //
 // See that PR for more details.
 trait MyTrait: Copy {
@@ -19,5 +19,7 @@ const fn output<T: MyTrait>(_: T) -> usize {
 
 fn main() {
     let x = [0u8; output(yeet())];
+    //~^ ERROR unable to use constant with a hidden value in the type system
     println!("{:?}", x);
+    //~^ ERROR unable to use constant with a hidden value in the type system
 }

src/test/ui/impl-trait/in-ctfe/array-len.stderr

@@ -0,0 +1,16 @@
+error: unable to use constant with a hidden value in the type system
+  --> $DIR/array-len.rs:21:19
+   |
+LL |     let x = [0u8; output(yeet())];
+   |                   ^^^^^^^^^^^^^^
+
+error: unable to use constant with a hidden value in the type system
+  --> $DIR/array-len.rs:23:22
+   |
+LL |     println!("{:?}", x);
+   |                      ^
+   |
+   = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to 2 previous errors
+

src/test/ui/impl-trait/in-ctfe/enum-discr.rs

@@ -1,4 +1,4 @@
-// This previously compiled, but broke with #101478.
+// This previously compiled, but was intentionally changed in #101478.
 //
 // See that PR for more details.
 trait MyTrait: Copy {
@@ -20,6 +20,7 @@ const fn output<T: MyTrait>(_: T) -> usize {
 #[repr(usize)]
 enum Foo {
     Bar = output(yeet()),
+    //~^ ERROR unable to use constant with a hidden value in the type system
 }
 
 fn main() {

src/test/ui/impl-trait/in-ctfe/enum-discr.stderr

@@ -0,0 +1,8 @@
+error: unable to use constant with a hidden value in the type system
+  --> $DIR/enum-discr.rs:22:11
+   |
+LL |     Bar = output(yeet()),
+   |           ^^^^^^^^^^^^^^
+
+error: aborting due to previous error
+

src/test/ui/impl-trait/in-ctfe/match-arm-exhaustive.rs

@@ -1,4 +1,4 @@
-// This previously compiled, but broke with #101478.
+// This previously compiled, but was intentionally changed in #101478.
 //
 // See that PR for more details.
 trait MyTrait: Copy {
@@ -20,6 +20,8 @@ const CT: u8 = output(yeet());
 fn main() {
     match 0 {
         CT => (),
+        //~^ ERROR constant pattern depends on a generic parameter
+        //~| ERROR constant pattern depends on a generic parameter
         1.. => (),
     }
 }

src/test/ui/impl-trait/in-ctfe/match-arm-exhaustive.stderr

@@ -1,11 +1,11 @@
 error: constant pattern depends on a generic parameter
-  --> $DIR/match-arm-exhaustive.rs:19:9
+  --> $DIR/match-arm-exhaustive.rs:22:9
    |
 LL |         CT => (),
    |         ^^
 
 error: constant pattern depends on a generic parameter
-  --> $DIR/match-arm-exhaustive.rs:19:9
+  --> $DIR/match-arm-exhaustive.rs:22:9
    |
 LL |         CT => (),
    |         ^^

src/test/ui/issues/issue-77919.rs

@@ -1,5 +1,6 @@
 fn main() {
     [1; <Multiply<Five, Five>>::VAL];
+    //~^ ERROR unable to use constant with a hidden value in the type system
 }
 trait TypeVal<T> {
     const VAL: T;

src/test/ui/issues/issue-77919.stderr

@@ -1,5 +1,5 @@
 error[E0412]: cannot find type `PhantomData` in this scope
-  --> $DIR/issue-77919.rs:9:9
+  --> $DIR/issue-77919.rs:10:9
    |
 LL |     _n: PhantomData,
    |         ^^^^^^^^^^^ not found in this scope
@@ -10,23 +10,29 @@ LL | use std::marker::PhantomData;
    |
 
 error[E0412]: cannot find type `VAL` in this scope
-  --> $DIR/issue-77919.rs:11:63
+  --> $DIR/issue-77919.rs:12:63
    |
 LL | impl<N, M> TypeVal<usize> for Multiply<N, M> where N: TypeVal<VAL> {}
    |          -                                                    ^^^ not found in this scope
    |          |
    |          help: you might be missing a type parameter: `, VAL`
 
 error[E0046]: not all trait items implemented, missing: `VAL`
-  --> $DIR/issue-77919.rs:11:1
+  --> $DIR/issue-77919.rs:12:1
    |
 LL |     const VAL: T;
    |     ------------ `VAL` from trait
 ...
 LL | impl<N, M> TypeVal<usize> for Multiply<N, M> where N: TypeVal<VAL> {}
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ missing `VAL` in implementation
 
-error: aborting due to 3 previous errors
+error: unable to use constant with a hidden value in the type system
+  --> $DIR/issue-77919.rs:2:9
+   |
+LL |     [1; <Multiply<Five, Five>>::VAL];
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 4 previous errors
 
 Some errors have detailed explanations: E0046, E0412.
 For more information about an error, try `rustc --explain E0046`.

src/test/ui/specialization/ctfe/default-assoc-const.rs

@@ -0,0 +1,22 @@
+// ICE fixed by #101478.
+//
+// See that PR for more details.
+#![feature(specialization)]
+//~^ WARNING the feature `specialization` is incomplete and may not be safe to use
+
+trait Foo {
+    const ASSOC: usize;
+}
+
+
+impl Foo for u32 {
+    default const ASSOC: usize = 0;
+}
+
+fn foo() -> [u8; 0] {
+    [0; <u32 as Foo>::ASSOC]
+    //~^ ERROR unable to use constant with a hidden value in the type system
+    //~| ERROR mismatched types
+}
+
+fn main() {}

src/test/ui/specialization/ctfe/default-assoc-const.stderr

@@ -0,0 +1,30 @@
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/default-assoc-const.rs:4:12
+   |
+LL | #![feature(specialization)]
+   |            ^^^^^^^^^^^^^^
+   |
+   = note: `#[warn(incomplete_features)]` on by default
+   = note: see issue #31844 <https://github.com/rust-lang/rust/issues/31844> for more information
+   = help: consider using `min_specialization` instead, which is more stable and complete
+
+error[E0308]: mismatched types
+  --> $DIR/default-assoc-const.rs:17:5
+   |
+LL | fn foo() -> [u8; 0] {
+   |             ------- expected `[u8; 0]` because of return type
+LL |     [0; <u32 as Foo>::ASSOC]
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^ expected `0`, found `<u32 as Foo>::ASSOC`
+   |
+   = note: expected array `[u8; 0]`
+              found array `[u8; _]`
+
+error: unable to use constant with a hidden value in the type system
+  --> $DIR/default-assoc-const.rs:17:9
+   |
+LL |     [0; <u32 as Foo>::ASSOC]
+   |         ^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 2 previous errors; 1 warning emitted
+
+For more information about this error, try `rustc --explain E0308`.

src/test/ui/specialization/ctfe/default-assoc-type.rs

@@ -0,0 +1,29 @@
+// ICE fixed by #101478.
+//
+// See that PR for more details.
+#![feature(specialization)]
+//~^ WARNING the feature `specialization` is incomplete and may not be safe to use
+
+trait Foo {
+    type Assoc: Trait;
+}
+
+impl<T> Foo for Vec<T> {
+    default type Assoc = u32;
+}
+
+trait Trait {
+    const ASSOC: usize;
+}
+
+impl Trait for u32 {
+    const ASSOC: usize = 0;
+}
+
+fn foo() -> [u8; 0] {
+    [0; <<Vec<u32> as Foo>::Assoc as Trait>::ASSOC]
+    //~^ ERROR unable to use constant with a hidden value in the type system
+    //~| ERROR mismatched types
+}
+
+fn main() {}

src/test/ui/specialization/ctfe/default-assoc-type.stderr

@@ -0,0 +1,30 @@
+warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/default-assoc-type.rs:4:12
+   |
+LL | #![feature(specialization)]
+   |            ^^^^^^^^^^^^^^
+   |
+   = note: `#[warn(incomplete_features)]` on by default
+   = note: see issue #31844 <https://github.com/rust-lang/rust/issues/31844> for more information
+   = help: consider using `min_specialization` instead, which is more stable and complete
+
+error[E0308]: mismatched types
+  --> $DIR/default-assoc-type.rs:24:5
+   |
+LL | fn foo() -> [u8; 0] {
+   |             ------- expected `[u8; 0]` because of return type
+LL |     [0; <<Vec<u32> as Foo>::Assoc as Trait>::ASSOC]
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `0`, found `<<Vec<u32> as Foo>::Assoc as Trait>::ASSOC`
+   |
+   = note: expected array `[u8; 0]`
+              found array `[u8; _]`
+
+error: unable to use constant with a hidden value in the type system
+  --> $DIR/default-assoc-type.rs:24:9
+   |
+LL |     [0; <<Vec<u32> as Foo>::Assoc as Trait>::ASSOC]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 2 previous errors; 1 warning emitted
+
+For more information about this error, try `rustc --explain E0308`.