Overhaul const-checking diagnostics

compiler/rustc_mir/src/transform/check_consts/ops.rs

@@ -515,8 +515,6 @@ pub mod ty {
     #[derive(Debug)]
     pub struct MutRef;
     impl NonConstOp for MutRef {
-        const STOPS_CONST_CHECKING: bool = true;
-
         fn status_in_item(&self, _ccx: &ConstCx<'_, '_>) -> Status {
             Status::Unstable(sym::const_mut_refs)
         }

src/test/ui/consts/const-eval/assign-to-static-within-other-static-2.rs

@@ -1,7 +1,7 @@
 // New test for #53818: modifying static memory at compile-time is not allowed.
 // The test should never compile successfully
 
-#![feature(const_raw_ptr_deref)]
+#![feature(const_raw_ptr_deref, const_mut_refs)]
 
 use std::cell::UnsafeCell;
 
@@ -13,7 +13,7 @@ unsafe impl Sync for Foo {}
 static FOO: Foo = Foo(UnsafeCell::new(42));
 
 static BAR: () = unsafe {
-    *FOO.0.get() = 5; //~ ERROR contains unimplemented expression type
+    *FOO.0.get() = 5; //~ ERROR
 };
 
 fn main() {}

src/test/ui/consts/const-eval/assign-to-static-within-other-static-2.stderr

@@ -1,11 +1,9 @@
-error[E0019]: static contains unimplemented expression type
+error[E0080]: could not evaluate static initializer
   --> $DIR/assign-to-static-within-other-static-2.rs:16:5
    |
 LL |     *FOO.0.get() = 5;
-   |     ^^^^^^^^^^^^^^^^
-   |
-   = help: add `#![feature(const_mut_refs)]` to the crate attributes to enable
+   |     ^^^^^^^^^^^^^^^^ modifying a static's initial value from another static's initializer
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0019`.
+For more information about this error, try `rustc --explain E0080`.

src/test/ui/consts/const-eval/mod-static-with-const-fn.rs

@@ -12,14 +12,9 @@ unsafe impl Sync for Foo {}
 
 static FOO: Foo = Foo(UnsafeCell::new(42));
 
-fn foo() {}
-
 static BAR: () = unsafe {
     *FOO.0.get() = 5;
-    //~^ contains unimplemented expression
-
-    foo();
-    //~^ ERROR calls in statics are limited to constant functions, tuple structs and tuple variants
+    //~^ mutation through a reference
 };
 
 fn main() {

src/test/ui/consts/const-eval/mod-static-with-const-fn.stderr

@@ -1,18 +1,12 @@
-error[E0019]: static contains unimplemented expression type
-  --> $DIR/mod-static-with-const-fn.rs:18:5
+error[E0658]: mutation through a reference is not allowed in statics
+  --> $DIR/mod-static-with-const-fn.rs:15:5
    |
 LL |     *FOO.0.get() = 5;
    |     ^^^^^^^^^^^^^^^^
    |
+   = note: see issue #57349 <https://github.com/rust-lang/rust/issues/57349> for more information
    = help: add `#![feature(const_mut_refs)]` to the crate attributes to enable
 
-error[E0015]: calls in statics are limited to constant functions, tuple structs and tuple variants
-  --> $DIR/mod-static-with-const-fn.rs:21:5
-   |
-LL |     foo();
-   |     ^^^^^
-
-error: aborting due to 2 previous errors
+error: aborting due to previous error
 
-Some errors have detailed explanations: E0015, E0019.
-For more information about an error, try `rustc --explain E0015`.
+For more information about this error, try `rustc --explain E0658`.

src/test/ui/consts/const_let_assign3.rs

@@ -6,23 +6,21 @@ struct S {
 
 impl S {
     const fn foo(&mut self, x: u32) {
-        //~^ ERROR mutable references
+        //~^ ERROR mutable reference
         self.state = x;
     }
 }
 
 const FOO: S = {
     let mut s = S { state: 42 };
-    s.foo(3); //~ ERROR mutable references are not allowed in constants
+    s.foo(3); //~ ERROR mutable reference
     s
 };
 
 type Array = [u32; {
     let mut x = 2;
-    let y = &mut x;
-//~^ ERROR mutable references are not allowed in constants
+    let y = &mut x; //~ ERROR mutable reference
     *y = 42;
-//~^ ERROR constant contains unimplemented expression type
     *y
 }];
 

src/test/ui/consts/const_let_assign3.stderr

@@ -19,15 +19,7 @@ error[E0764]: mutable references are not allowed in constants
 LL |     let y = &mut x;
    |             ^^^^^^ `&mut` is only allowed in `const fn`
 
-error[E0019]: constant contains unimplemented expression type
-  --> $DIR/const_let_assign3.rs:24:5
-   |
-LL |     *y = 42;
-   |     ^^^^^^^
-   |
-   = help: add `#![feature(const_mut_refs)]` to the crate attributes to enable
-
-error: aborting due to 4 previous errors
+error: aborting due to 3 previous errors
 
-Some errors have detailed explanations: E0019, E0658, E0764.
-For more information about an error, try `rustc --explain E0019`.
+Some errors have detailed explanations: E0658, E0764.
+For more information about an error, try `rustc --explain E0658`.

src/test/ui/consts/min_const_fn/bad_const_fn_body_ice.rs

@@ -1,7 +1,6 @@
 const fn foo(a: i32) -> Vec<i32> {
     vec![1, 2, 3]
     //~^ ERROR allocations are not allowed
-    //~| ERROR unimplemented expression type
     //~| ERROR calls in constant functions
 }
 

src/test/ui/consts/min_const_fn/bad_const_fn_body_ice.stderr

@@ -6,15 +6,6 @@ LL |     vec![1, 2, 3]
    |
    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error[E0019]: constant function contains unimplemented expression type
-  --> $DIR/bad_const_fn_body_ice.rs:2:5
-   |
-LL |     vec![1, 2, 3]
-   |     ^^^^^^^^^^^^^
-   |
-   = help: add `#![feature(const_mut_refs)]` to the crate attributes to enable
-   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
-
 error[E0015]: calls in constant functions are limited to constant functions, tuple structs and tuple variants
   --> $DIR/bad_const_fn_body_ice.rs:2:5
    |
@@ -23,7 +14,7 @@ LL |     vec![1, 2, 3]
    |
    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error: aborting due to 3 previous errors
+error: aborting due to 2 previous errors
 
-Some errors have detailed explanations: E0010, E0015, E0019.
+Some errors have detailed explanations: E0010, E0015.
 For more information about an error, try `rustc --explain E0010`.

src/test/ui/consts/min_const_fn/min_const_fn.rs

@@ -38,25 +38,37 @@ impl<T> Foo<T> {
     const fn get(&self) -> &T { &self.0 }
     const fn get_mut(&mut self) -> &mut T { &mut self.0 }
     //~^ mutable references
+    //~| mutable references
+    //~| mutable references
+    //~| mutable references
 }
 impl<'a, T> Foo<T> {
     const fn new_lt(t: T) -> Self { Foo(t) }
     const fn into_inner_lt(self) -> T { self.0 } //~ destructors cannot be evaluated
     const fn get_lt(&'a self) -> &T { &self.0 }
     const fn get_mut_lt(&'a mut self) -> &mut T { &mut self.0 }
     //~^ mutable references
+    //~| mutable references
+    //~| mutable references
+    //~| mutable references
 }
 impl<T: Sized> Foo<T> {
     const fn new_s(t: T) -> Self { Foo(t) }
     const fn into_inner_s(self) -> T { self.0 } //~ ERROR destructors
     const fn get_s(&self) -> &T { &self.0 }
     const fn get_mut_s(&mut self) -> &mut T { &mut self.0 }
     //~^ mutable references
+    //~| mutable references
+    //~| mutable references
+    //~| mutable references
 }
 impl<T: ?Sized> Foo<T> {
     const fn get_sq(&self) -> &T { &self.0 }
     const fn get_mut_sq(&mut self) -> &mut T { &mut self.0 }
     //~^ mutable references
+    //~| mutable references
+    //~| mutable references
+    //~| mutable references
 }