Fix up tests

Author: oli-obk

src/test/ui/rfc-2632-const-trait-impl/staged-api-user-crate.rs

@@ -0,0 +1,16 @@
+// aux-build: staged-api.rs
+extern crate staged_api;
+
+use staged_api::*;
+
+// Const stability has no impact on usage in non-const contexts.
+fn non_const_context() {
+    Unstable::func();
+}
+
+const fn stable_const_context() {
+    Unstable::func();
+    //~^ ERROR cannot call non-const fn `<staged_api::Unstable as staged_api::MyTrait>::func` in constant functions
+}
+
+fn main() {}

src/test/ui/rfc-2632-const-trait-impl/staged-api-user-crate.stderr

@@ -0,0 +1,11 @@
+error[E0015]: cannot call non-const fn `<staged_api::Unstable as staged_api::MyTrait>::func` in constant functions
+  --> $DIR/staged-api-user-crate.rs:12:5
+   |
+LL |     Unstable::func();
+   |     ^^^^^^^^^^^^^^^^
+   |
+   = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0015`.

src/test/ui/rfc-2632-const-trait-impl/staged-api.rs

@@ -33,15 +33,31 @@ const fn const_context() {
     // ^ This is okay regardless of whether the `unstable` feature is enabled, as this function is
     // not const-stable.
     Foo::func();
-    //[unstable]~^ not yet stable as a const fn
+    //[unstable]~^ ERROR not yet stable as a const fn
+    // ^ fails, because the `foo` feature is not active
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
+#[cfg_attr(unstable, rustc_const_unstable(feature = "foo", issue = "none"))]
+pub const fn const_context_not_const_stable() {
+    //[stable]~^ ERROR function has missing const stability attribute
+    Unstable::func();
+    // ^ This is okay regardless of whether the `unstable` feature is enabled, as this function is
+    // not const-stable.
+    Foo::func();
+    //[unstable]~^ ERROR not yet stable as a const fn
+    // ^ fails, because the `foo` feature is not active
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+#[rustc_const_stable(feature = "cheese", since = "1.0.0")]
 const fn stable_const_context() {
     Unstable::func();
     //[unstable]~^ ERROR not yet stable as a const fn
     Foo::func();
     //[unstable]~^ ERROR not yet stable as a const fn
+    const_context_not_const_stable()
+    //[unstable]~^ ERROR not yet stable as a const fn
 }
 
 fn main() {}

src/test/ui/rfc-2632-const-trait-impl/staged-api.stable.stderr

@@ -9,5 +9,17 @@ LL | | }
    |
    = note: see issue #67792 <https://github.com/rust-lang/rust/issues/67792> for more information
 
-error: aborting due to previous error
+error: function has missing const stability attribute
+  --> $DIR/staged-api.rs:42:1
+   |
+LL | / pub const fn const_context_not_const_stable() {
+LL | |
+LL | |     Unstable::func();
+LL | |     // ^ This is okay regardless of whether the `unstable` feature is enabled, as this function is
+...  |
+LL | |     // ^ fails, because the `foo` feature is not active
+LL | | }
+   | |_^
+
+error: aborting due to 2 previous errors
 

src/test/ui/rfc-2632-const-trait-impl/staged-api.unstable.stderr

@@ -7,12 +7,36 @@ LL |     Foo::func();
    = help: add `#![feature(foo)]` to the crate attributes to enable
 
 error: `<Foo as staged_api::MyTrait>::func` is not yet stable as a const fn
-  --> $DIR/staged-api.rs:43:5
+  --> $DIR/staged-api.rs:47:5
    |
 LL |     Foo::func();
    |     ^^^^^^^^^^^
    |
    = help: add `#![feature(foo)]` to the crate attributes to enable
 
-error: aborting due to 2 previous errors
+error: `<staged_api::Unstable as staged_api::MyTrait>::func` is not yet stable as a const fn
+  --> $DIR/staged-api.rs:55:5
+   |
+LL |     Unstable::func();
+   |     ^^^^^^^^^^^^^^^^
+   |
+   = help: const-stable functions can only call other const-stable functions
+
+error: `<Foo as staged_api::MyTrait>::func` is not yet stable as a const fn
+  --> $DIR/staged-api.rs:57:5
+   |
+LL |     Foo::func();
+   |     ^^^^^^^^^^^
+   |
+   = help: const-stable functions can only call other const-stable functions
+
+error: `const_context_not_const_stable` is not yet stable as a const fn
+  --> $DIR/staged-api.rs:59:5
+   |
+LL |     const_context_not_const_stable()
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: const-stable functions can only call other const-stable functions
+
+error: aborting due to 5 previous errors