update diagnostics for &mut in constants

pvdrz · pvdrz · commit 1f48465a0147 · 2020-06-19T11:48:46.000-05:00
diff --git a/src/librustc_mir/transform/check_consts/ops.rs b/src/librustc_mir/transform/check_consts/ops.rs
@@ -216,17 +216,23 @@ impl NonConstOp for MutBorrow {
     }
 
     fn emit_error(&self, ccx: &ConstCx<'_, '_>, span: Span) {
-        let mut err = feature_err(
-            &ccx.tcx.sess.parse_sess,
-            sym::const_mut_refs,
-            span,
-            &format!(
-                "references in {}s may only refer \
-                      to immutable values",
-                ccx.const_kind()
-            ),
-        );
-        err.span_label(span, format!("{}s require immutable values", ccx.const_kind()));
+        let mut err = if ccx.const_kind() == hir::ConstContext::ConstFn {
+            feature_err(
+                &ccx.tcx.sess.parse_sess,
+                sym::const_mut_refs,
+                span,
+                &format!("mutable references are not allowed in {}s", ccx.const_kind()),
+            )
+        } else {
+            struct_span_err!(
+                ccx.tcx.sess,
+                span,
+                E0019,
+                "mutable references are not allowed in {}s",
+                ccx.const_kind(),
+            )
+        };
+        err.span_label(span, "`&mut` is only allowed in `const fn`".to_string());
         if ccx.tcx.sess.teach(&err.get_code().unwrap()) {
             err.note(
                 "References in statics and constants may only refer \
diff --git a/src/test/compile-fail/issue-52443.rs b/src/test/compile-fail/issue-52443.rs
@@ -9,7 +9,7 @@ fn main() {
     [(); { for _ in 0usize.. {}; 0}];
     //~^ ERROR `for` is not allowed in a `const`
     //~| ERROR calls in constants are limited to constant functions
-    //~| ERROR references in constants may only refer to immutable values
+    //~| ERROR mutable references are not allowed in constants
     //~| ERROR calls in constants are limited to constant functions
     //~| ERROR evaluation of constant value failed
 }
diff --git a/src/test/ui/check-static-immutable-mut-slices.rs b/src/test/ui/check-static-immutable-mut-slices.rs
@@ -1,6 +1,6 @@
 // Checks that immutable static items can't have mutable slices
 
 static TEST: &'static mut [isize] = &mut [];
-//~^ ERROR references in statics may only refer to immutable values
+//~^ ERROR mutable references are not allowed in statics
 
 pub fn main() { }
diff --git a/src/test/ui/check-static-immutable-mut-slices.stderr b/src/test/ui/check-static-immutable-mut-slices.stderr
@@ -1,12 +1,9 @@
-error[E0658]: references in statics may only refer to immutable values
+error[E0019]: mutable references are not allowed in statics
   --> $DIR/check-static-immutable-mut-slices.rs:3:37
    |
 LL | static TEST: &'static mut [isize] = &mut [];
-   |                                     ^^^^^^^ statics require immutable values
-   |
-   = 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
+   |                                     ^^^^^^^ `&mut` is only allowed in `const fn`
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0658`.
+For more information about this error, try `rustc --explain E0019`.
diff --git a/src/test/ui/consts/const-eval/issue-65394.rs b/src/test/ui/consts/const-eval/issue-65394.rs
@@ -5,7 +5,7 @@
 
 const _: Vec<i32> = {
     let mut x = Vec::<i32>::new(); //~ ERROR destructors cannot be evaluated at compile-time
-    let r = &mut x; //~ ERROR references in constants may only refer to immutable values
+    let r = &mut x; //~ ERROR mutable references are not allowed in constants
     let y = x;
     y
 };
diff --git a/src/test/ui/consts/const-eval/issue-65394.stderr b/src/test/ui/consts/const-eval/issue-65394.stderr
@@ -1,11 +1,8 @@
-error[E0658]: references in constants may only refer to immutable values
+error[E0019]: mutable references are not allowed in constants
   --> $DIR/issue-65394.rs:8:13
    |
 LL |     let r = &mut x;
-   |             ^^^^^^ constants require immutable values
-   |
-   = 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
+   |             ^^^^^^ `&mut` is only allowed in `const fn`
 
 error[E0493]: destructors cannot be evaluated at compile-time
   --> $DIR/issue-65394.rs:7:9
@@ -15,5 +12,5 @@ LL |     let mut x = Vec::<i32>::new();
 
 error: aborting due to 2 previous errors
 
-Some errors have detailed explanations: E0493, E0658.
-For more information about an error, try `rustc --explain E0493`.
+Some errors have detailed explanations: E0019, E0493.
+For more information about an error, try `rustc --explain E0019`.
diff --git a/src/test/ui/consts/const-multi-ref.rs b/src/test/ui/consts/const-multi-ref.rs
@@ -3,7 +3,7 @@
 
 const _: i32 = {
     let mut a = 5;
-    let p = &mut a; //~ ERROR references in constants may only refer to immutable values
+    let p = &mut a; //~ ERROR mutable references are not allowed in constants
 
     let reborrow = {p};
     let pp = &reborrow;
diff --git a/src/test/ui/consts/const-multi-ref.stderr b/src/test/ui/consts/const-multi-ref.stderr
@@ -1,11 +1,8 @@
-error[E0658]: references in constants may only refer to immutable values
+error[E0019]: mutable references are not allowed in constants
   --> $DIR/const-multi-ref.rs:6:13
    |
 LL |     let p = &mut a;
-   |             ^^^^^^ constants require immutable values
-   |
-   = 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
+   |             ^^^^^^ `&mut` is only allowed in `const fn`
 
 error[E0492]: cannot borrow a constant which may contain interior mutability, create a static instead
   --> $DIR/const-multi-ref.rs:16:13
@@ -15,5 +12,5 @@ LL |     let p = &a;
 
 error: aborting due to 2 previous errors
 
-Some errors have detailed explanations: E0492, E0658.
-For more information about an error, try `rustc --explain E0492`.
+Some errors have detailed explanations: E0019, E0492.
+For more information about an error, try `rustc --explain E0019`.
diff --git a/src/test/ui/consts/const-mut-refs/const_mut_address_of.rs b/src/test/ui/consts/const-mut-refs/const_mut_address_of.rs
@@ -22,9 +22,9 @@ const fn baz(foo: &mut Foo)-> *mut usize {
 
 const _: () = {
     foo().bar();
-    //~^ ERROR references in constants may only refer to immutable values
+    //~^ ERROR mutable references are not allowed in constants
     baz(&mut foo());
-    //~^ ERROR references in constants may only refer to immutable values
+    //~^ ERROR mutable references are not allowed in constants
 };
 
 fn main() {}
diff --git a/src/test/ui/consts/const-mut-refs/const_mut_address_of.stderr b/src/test/ui/consts/const-mut-refs/const_mut_address_of.stderr
@@ -1,21 +1,15 @@
-error[E0658]: references in constants may only refer to immutable values
+error[E0019]: mutable references are not allowed in constants
   --> $DIR/const_mut_address_of.rs:24:5
    |
 LL |     foo().bar();
-   |     ^^^^^ constants require immutable values
-   |
-   = 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
+   |     ^^^^^ `&mut` is only allowed in `const fn`
 
-error[E0658]: references in constants may only refer to immutable values
+error[E0019]: mutable references are not allowed in constants
   --> $DIR/const_mut_address_of.rs:26:9
    |
 LL |     baz(&mut foo());
-   |         ^^^^^^^^^^ constants require immutable values
-   |
-   = 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
+   |         ^^^^^^^^^^ `&mut` is only allowed in `const fn`
 
 error: aborting due to 2 previous errors
 
-For more information about this error, try `rustc --explain E0658`.
+For more information about this error, try `rustc --explain E0019`.
diff --git a/src/test/ui/consts/const-mut-refs/const_mut_refs.rs b/src/test/ui/consts/const-mut-refs/const_mut_refs.rs
@@ -29,9 +29,9 @@ const fn bazz(foo: &mut Foo) -> usize {
 
 fn main() {
     let _: [(); foo().bar()] = [(); 1];
-    //~^ ERROR references in constants may only refer to immutable values
+    //~^ ERROR mutable references are not allowed in constants
     let _: [(); baz(&mut foo())] = [(); 2];
-    //~^ ERROR references in constants may only refer to immutable values
+    //~^ ERROR mutable references are not allowed in constants
     let _: [(); bazz(&mut foo())] = [(); 3];
-    //~^ ERROR references in constants may only refer to immutable values
+    //~^ ERROR mutable references are not allowed in constants
 }
diff --git a/src/test/ui/consts/const-mut-refs/const_mut_refs.stderr b/src/test/ui/consts/const-mut-refs/const_mut_refs.stderr
@@ -1,30 +1,21 @@
-error[E0658]: references in constants may only refer to immutable values
+error[E0019]: mutable references are not allowed in constants
   --> $DIR/const_mut_refs.rs:31:17
    |
 LL |     let _: [(); foo().bar()] = [(); 1];
-   |                 ^^^^^ constants require immutable values
-   |
-   = 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
+   |                 ^^^^^ `&mut` is only allowed in `const fn`
 
-error[E0658]: references in constants may only refer to immutable values
+error[E0019]: mutable references are not allowed in constants
   --> $DIR/const_mut_refs.rs:33:21
    |
 LL |     let _: [(); baz(&mut foo())] = [(); 2];
-   |                     ^^^^^^^^^^ constants require immutable values
-   |
-   = 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
+   |                     ^^^^^^^^^^ `&mut` is only allowed in `const fn`
 
-error[E0658]: references in constants may only refer to immutable values
+error[E0019]: mutable references are not allowed in constants
   --> $DIR/const_mut_refs.rs:35:22
    |
 LL |     let _: [(); bazz(&mut foo())] = [(); 3];
-   |                      ^^^^^^^^^^ constants require immutable values
-   |
-   = 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
+   |                      ^^^^^^^^^^ `&mut` is only allowed in `const fn`
 
 error: aborting due to 3 previous errors
 
-For more information about this error, try `rustc --explain E0658`.
+For more information about this error, try `rustc --explain E0019`.
diff --git a/src/test/ui/consts/const_let_assign3.rs b/src/test/ui/consts/const_let_assign3.rs
@@ -13,14 +13,14 @@ impl S {
 
 const FOO: S = {
     let mut s = S { state: 42 };
-    s.foo(3); //~ ERROR references in constants may only refer to immutable values
+    s.foo(3); //~ ERROR mutable references are not allowed in constants
     s
 };
 
 type Array = [u32; {
     let mut x = 2;
     let y = &mut x;
-//~^ ERROR references in constants may only refer to immutable values
+//~^ ERROR mutable references are not allowed in constants
     *y = 42;
 //~^ ERROR constant contains unimplemented expression type
     *y
diff --git a/src/test/ui/consts/const_let_assign3.stderr b/src/test/ui/consts/const_let_assign3.stderr
@@ -6,23 +6,17 @@ LL |         self.state = x;
    |
    = help: add `#![feature(const_mut_refs)]` to the crate attributes to enable
 
-error[E0658]: references in constants may only refer to immutable values
+error[E0019]: mutable references are not allowed in constants
   --> $DIR/const_let_assign3.rs:16:5
    |
 LL |     s.foo(3);
-   |     ^ constants require immutable values
-   |
-   = 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
+   |     ^ `&mut` is only allowed in `const fn`
 
-error[E0658]: references in constants may only refer to immutable values
+error[E0019]: mutable references are not allowed in constants
   --> $DIR/const_let_assign3.rs:22:13
    |
 LL |     let y = &mut x;
-   |             ^^^^^^ constants require immutable values
-   |
-   = 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
+   |             ^^^^^^ `&mut` is only allowed in `const fn`
 
 error[E0019]: constant contains unimplemented expression type
   --> $DIR/const_let_assign3.rs:24:5
@@ -34,5 +28,4 @@ LL |     *y = 42;
 
 error: aborting due to 4 previous errors
 
-Some errors have detailed explanations: E0019, E0658.
-For more information about an error, try `rustc --explain E0019`.
+For more information about this error, try `rustc --explain E0019`.
diff --git a/src/test/ui/consts/projection_qualif.mut_refs.stderr b/src/test/ui/consts/projection_qualif.mut_refs.stderr
@@ -1,11 +1,8 @@
-error[E0658]: references in constants may only refer to immutable values
+error[E0019]: mutable references are not allowed in constants
   --> $DIR/projection_qualif.rs:10:27
    |
 LL |         let b: *mut u32 = &mut a;
-   |                           ^^^^^^ constants require immutable values
-   |
-   = 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
+   |                           ^^^^^^ `&mut` is only allowed in `const fn`
 
 error[E0658]: dereferencing raw pointers in constants is unstable
   --> $DIR/projection_qualif.rs:11:18
@@ -18,4 +15,5 @@ LL |         unsafe { *b = 5; }
 
 error: aborting due to 2 previous errors
 
-For more information about this error, try `rustc --explain E0658`.
+Some errors have detailed explanations: E0019, E0658.
+For more information about an error, try `rustc --explain E0019`.
diff --git a/src/test/ui/consts/projection_qualif.rs b/src/test/ui/consts/projection_qualif.rs
@@ -7,7 +7,7 @@ use std::cell::Cell;
 const FOO: &u32 = {
     let mut a = 42;
     {
-        let b: *mut u32 = &mut a; //~ ERROR may only refer to immutable values
+        let b: *mut u32 = &mut a; //~ ERROR mutable references are not allowed in constants
         unsafe { *b = 5; } //~ ERROR dereferencing raw pointers in constants
         //[stock]~^ contains unimplemented expression
     }
diff --git a/src/test/ui/consts/projection_qualif.stock.stderr b/src/test/ui/consts/projection_qualif.stock.stderr
@@ -1,11 +1,8 @@
-error[E0658]: references in constants may only refer to immutable values
+error[E0019]: mutable references are not allowed in constants
   --> $DIR/projection_qualif.rs:10:27
    |
 LL |         let b: *mut u32 = &mut a;
-   |                           ^^^^^^ constants require immutable values
-   |
-   = 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
+   |                           ^^^^^^ `&mut` is only allowed in `const fn`
 
 error[E0658]: dereferencing raw pointers in constants is unstable
   --> $DIR/projection_qualif.rs:11:18
diff --git a/src/test/ui/consts/read_from_static_mut_ref.rs b/src/test/ui/consts/read_from_static_mut_ref.rs
@@ -1,8 +1,9 @@
+// We are keeping this test in case we decide to allow mutable references in statics again
 #![feature(const_mut_refs)]
 #![allow(const_err)]
 
 static OH_NO: &mut i32 = &mut 42;
-//~^ ERROR references in statics may only refer to immutable values
+//~^ ERROR mutable references are not allowed in statics
 fn main() {
     assert_eq!(*OH_NO, 42);
 }
diff --git a/src/test/ui/consts/read_from_static_mut_ref.stderr b/src/test/ui/consts/read_from_static_mut_ref.stderr
@@ -1,12 +1,9 @@
-error[E0658]: references in statics may only refer to immutable values
-  --> $DIR/read_from_static_mut_ref.rs:4:26
+error[E0019]: mutable references are not allowed in statics
+  --> $DIR/read_from_static_mut_ref.rs:5:26
    |
 LL | static OH_NO: &mut i32 = &mut 42;
-   |                          ^^^^^^^ statics require immutable values
-   |
-   = 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
+   |                          ^^^^^^^ `&mut` is only allowed in `const fn`
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0658`.
+For more information about this error, try `rustc --explain E0019`.
diff --git a/src/test/ui/consts/static_mut_containing_mut_ref2.mut_refs.stderr b/src/test/ui/consts/static_mut_containing_mut_ref2.mut_refs.stderr
@@ -1,12 +1,9 @@
-error[E0658]: references in statics may only refer to immutable values
+error[E0019]: mutable references are not allowed in statics
   --> $DIR/static_mut_containing_mut_ref2.rs:7:46
    |
 LL | pub static mut STDERR_BUFFER: () = unsafe { *(&mut STDERR_BUFFER_SPACE) = 42; };
-   |                                              ^^^^^^^^^^^^^^^^^^^^^^^^^^ statics require immutable values
-   |
-   = 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
+   |                                              ^^^^^^^^^^^^^^^^^^^^^^^^^^ `&mut` is only allowed in `const fn`
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0658`.
+For more information about this error, try `rustc --explain E0019`.
diff --git a/src/test/ui/consts/static_mut_containing_mut_ref2.rs b/src/test/ui/consts/static_mut_containing_mut_ref2.rs
@@ -5,7 +5,7 @@
 static mut STDERR_BUFFER_SPACE: u8 = 0;
 
 pub static mut STDERR_BUFFER: () = unsafe { *(&mut STDERR_BUFFER_SPACE) = 42; };
-//~^ ERROR references in statics may only refer to immutable values
+//~^ ERROR  mutable references are not allowed in statics
 //[stock]~| ERROR static contains unimplemented expression type
 
 fn main() {}
diff --git a/src/test/ui/consts/static_mut_containing_mut_ref2.stock.stderr b/src/test/ui/consts/static_mut_containing_mut_ref2.stock.stderr
@@ -1,11 +1,8 @@
-error[E0658]: references in statics may only refer to immutable values
+error[E0019]: mutable references are not allowed in statics
   --> $DIR/static_mut_containing_mut_ref2.rs:7:46
    |
 LL | pub static mut STDERR_BUFFER: () = unsafe { *(&mut STDERR_BUFFER_SPACE) = 42; };
-   |                                              ^^^^^^^^^^^^^^^^^^^^^^^^^^ statics require immutable values
-   |
-   = 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
+   |                                              ^^^^^^^^^^^^^^^^^^^^^^^^^^ `&mut` is only allowed in `const fn`
 
 error[E0019]: static contains unimplemented expression type
   --> $DIR/static_mut_containing_mut_ref2.rs:7:45
@@ -17,5 +14,4 @@ LL | pub static mut STDERR_BUFFER: () = unsafe { *(&mut STDERR_BUFFER_SPACE) = 4
 
 error: aborting due to 2 previous errors
 
-Some errors have detailed explanations: E0019, E0658.
-For more information about an error, try `rustc --explain E0019`.
+For more information about this error, try `rustc --explain E0019`.
diff --git a/src/test/ui/error-codes/E0017.rs b/src/test/ui/error-codes/E0017.rs
diff --git a/src/test/ui/error-codes/E0017.stderr b/src/test/ui/error-codes/E0017.stderr
diff --git a/src/test/ui/error-codes/E0388.rs b/src/test/ui/error-codes/E0388.rs
diff --git a/src/test/ui/error-codes/E0388.stderr b/src/test/ui/error-codes/E0388.stderr
diff --git a/src/test/ui/issues/issue-17718-const-bad-values.rs b/src/test/ui/issues/issue-17718-const-bad-values.rs
diff --git a/src/test/ui/issues/issue-17718-const-bad-values.stderr b/src/test/ui/issues/issue-17718-const-bad-values.stderr
diff --git a/src/test/ui/issues/issue-46604.rs b/src/test/ui/issues/issue-46604.rs
diff --git a/src/test/ui/issues/issue-46604.stderr b/src/test/ui/issues/issue-46604.stderr

Original file line number	Diff line number	Diff line change
`@@ -9,7 +9,7 @@ fn main() {`
`9`	`9`	`[(); { for _ in 0usize.. {}; 0}];`
`10`	`10`	//~^ ERROR `for` is not allowed in a `const`
`11`	`11`	`//~\| ERROR calls in constants are limited to constant functions`
`12`		`- //~\| ERROR references in constants may only refer to immutable values`
	`12`	`+ //~\| ERROR mutable references are not allowed in constants`
`13`	`13`	`//~\| ERROR calls in constants are limited to constant functions`
`14`	`14`	`//~\| ERROR evaluation of constant value failed`
`15`	`15`	`}`
Original file line number	Diff line number	Diff line change
`@@ -5,7 +5,7 @@`
`5`	`5`
`6`	`6`	`const _: Vec<i32> = {`
`7`	`7`	`let mut x = Vec::<i32>::new(); //~ ERROR destructors cannot be evaluated at compile-time`
`8`		`- let r = &mut x; //~ ERROR references in constants may only refer to immutable values`
	`8`	`+ let r = &mut x; //~ ERROR mutable references are not allowed in constants`
`9`	`9`	`let y = x;`
`10`	`10`	`y`
`11`	`11`	`};`