Auto merge of #127176 - fee1-dead-contrib:fx-requires-next-solver, r=compiler-errors

Make `feature(effects)` require `-Znext-solver`

Per #120639 (review)

I made this a hard error because otherwise it should be a lint and that seemed more complicated. Not sure if this is the best place to put the error though.

r? project-const-traits

Author: bors

compiler/rustc_hir_analysis/messages.ftl

@@ -120,6 +120,10 @@ hir_analysis_drop_impl_reservation = reservation `Drop` impls are not supported
 hir_analysis_duplicate_precise_capture = cannot capture parameter `{$name}` twice
     .label = parameter captured again here
 
+hir_analysis_effects_without_next_solver = using `#![feature(effects)]` without enabling next trait solver globally
+    .note = the next trait solver must be enabled globally for the effects feature to work correctly
+    .help = use `-Znext-solver` to enable
+
 hir_analysis_empty_specialization = specialization impl does not specialize any associated items
     .note = impl is a specialization of this impl
 

compiler/rustc_hir_analysis/src/errors.rs

@@ -1699,3 +1699,9 @@ pub struct InvalidReceiverTy<'tcx> {
     pub span: Span,
     pub receiver_ty: Ty<'tcx>,
 }
+
+#[derive(Diagnostic)]
+#[diag(hir_analysis_effects_without_next_solver)]
+#[note]
+#[help]
+pub struct EffectsWithoutNextSolver;

compiler/rustc_hir_analysis/src/lib.rs

@@ -151,6 +151,12 @@ pub fn provide(providers: &mut Providers) {
 pub fn check_crate(tcx: TyCtxt<'_>) {
     let _prof_timer = tcx.sess.timer("type_check_crate");
 
+    // FIXME(effects): remove once effects is implemented in old trait solver
+    // or if the next solver is stabilized.
+    if tcx.features().effects && !tcx.next_trait_solver_globally() {
+        tcx.dcx().emit_err(errors::EffectsWithoutNextSolver);
+    }
+
     tcx.sess.time("coherence_checking", || {
         tcx.hir().par_for_each_module(|module| {
             let _ = tcx.ensure().check_mod_type_wf(module);

tests/crashes/119924-6.rs

@@ -1,4 +1,5 @@
 //@ known-bug: #119924
+//@ compile-flags: -Znext-solver
 #![feature(const_trait_impl, effects)]
 
 struct S;

tests/rustdoc/inline_cross/auxiliary/const-effect-param.rs

@@ -1,4 +1,6 @@
+//@ compile-flags: -Znext-solver
 #![feature(effects, const_trait_impl)]
+#![allow(incomplete_features)]
 
 #[const_trait]
 pub trait Resource {}

tests/ui/const-generics/generic_const_exprs/unify-op-with-fn-call.rs

@@ -1,5 +1,5 @@
 //@ known-bug: #110395
-
+//@ compile-flags: -Znext-solver
 #![feature(generic_const_exprs, adt_const_params, const_trait_impl, effects)]
 #![allow(incomplete_features)]
 

tests/ui/const-generics/generic_const_exprs/unify-op-with-fn-call.stderr

@@ -19,6 +19,12 @@ LL + #[derive(ConstParamTy)]
 LL | struct Foo(u8);
    |
 
+error[E0284]: type annotations needed: cannot normalize `foo<N>::{constant#0}`
+  --> $DIR/unify-op-with-fn-call.rs:20:25
+   |
+LL | fn foo<const N: Foo>(a: Evaluatable<{ N + N }>) {
+   |                         ^^^^^^^^^^^^^^^^^^^^^^ cannot normalize `foo<N>::{constant#0}`
+
 error[E0741]: `Foo` must implement `ConstParamTy` to be used as the type of a const generic parameter
   --> $DIR/unify-op-with-fn-call.rs:20:17
    |
@@ -43,17 +49,25 @@ LL + #[derive(ConstParamTy)]
 LL | struct Foo(u8);
    |
 
-error: unconstrained generic constant
-  --> $DIR/unify-op-with-fn-call.rs:30:12
+error[E0284]: type annotations needed: cannot normalize `foo2<N>::{constant#0}`
+  --> $DIR/unify-op-with-fn-call.rs:29:28
    |
-LL |     bar2::<{ std::ops::Add::add(N, N) }>();
-   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | fn foo2<const N: usize>(a: Evaluatable2<{ N + N }>) {
+   |                            ^^^^^^^^^^^^^^^^^^^^^^^ cannot normalize `foo2<N>::{constant#0}`
+
+error[E0284]: type annotations needed: cannot normalize `foo<N>::{constant#0}`
+  --> $DIR/unify-op-with-fn-call.rs:21:11
    |
-help: try adding a `where` bound
+LL |     bar::<{ std::ops::Add::add(N, N) }>();
+   |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot normalize `foo<N>::{constant#0}`
+
+error[E0284]: type annotations needed: cannot normalize `foo2<N>::{constant#0}`
+  --> $DIR/unify-op-with-fn-call.rs:30:12
    |
-LL | fn foo2<const N: usize>(a: Evaluatable2<{ N + N }>) where [(); { std::ops::Add::add(N, N) }]: {
-   |                                                     +++++++++++++++++++++++++++++++++++++++++
+LL |     bar2::<{ std::ops::Add::add(N, N) }>();
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot normalize `foo2<N>::{constant#0}`
 
-error: aborting due to 5 previous errors
+error: aborting due to 8 previous errors
 
-For more information about this error, try `rustc --explain E0741`.
+Some errors have detailed explanations: E0284, E0741.
+For more information about an error, try `rustc --explain E0284`.

tests/ui/const-generics/issues/issue-88119.rs

@@ -1,5 +1,5 @@
-//@ check-pass
-
+//@ known-bug: #110395
+//@ compile-flags: -Znext-solver
 #![allow(incomplete_features)]
 #![feature(const_trait_impl, effects, generic_const_exprs)]
 

tests/ui/const-generics/issues/issue-88119.stderr

@@ -0,0 +1,27 @@
+error[E0284]: type annotations needed: cannot satisfy `the constant `name_len::<T>()` can be evaluated`
+  --> $DIR/issue-88119.rs:21:5
+   |
+LL |     [(); name_len::<T>()]:,
+   |     ^^^^^^^^^^^^^^^^^^^^^ cannot satisfy `the constant `name_len::<T>()` can be evaluated`
+   |
+note: required by a bound in `<&T as ConstName>`
+  --> $DIR/issue-88119.rs:21:10
+   |
+LL |     [(); name_len::<T>()]:,
+   |          ^^^^^^^^^^^^^^^ required by this bound in `<&T as ConstName>`
+
+error[E0284]: type annotations needed: cannot satisfy `the constant `name_len::<T>()` can be evaluated`
+  --> $DIR/issue-88119.rs:28:5
+   |
+LL |     [(); name_len::<T>()]:,
+   |     ^^^^^^^^^^^^^^^^^^^^^ cannot satisfy `the constant `name_len::<T>()` can be evaluated`
+   |
+note: required by a bound in `<&mut T as ConstName>`
+  --> $DIR/issue-88119.rs:28:10
+   |
+LL |     [(); name_len::<T>()]:,
+   |          ^^^^^^^^^^^^^^^ required by this bound in `<&mut T as ConstName>`
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0284`.

tests/ui/consts/auxiliary/closure-in-foreign-crate.rs

@@ -1,5 +1,7 @@
+//@ compile-flags: -Znext-solver
 #![crate_type = "lib"]
-#![feature(const_closures, const_trait_impl, effects)] //~ WARN the feature `effects` is incomplete
+#![feature(const_closures, const_trait_impl, effects)]
+#![allow(incomplete_features)]
 
 pub const fn test() {
     let cl = const || {};