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
+