Never stop due to errors before borrow checking

2024-11-28 01:34:21 +00:00 · 2019-04-15 12:54:18 -07:00 · 2019-04-15 12:54:18 -07:00 · 6e723c24a8
commit 6e723c24a8
parent c21fbfe7e3
49 changed files with 409 additions and 108 deletions
--- a/src/librustc_interface/passes.rs
+++ b/src/librustc_interface/passes.rs
@ -936,13 +936,6 @@ fn analysis<'tcx>(
        });
    });

-    // Abort so we don't try to construct MIR with liveness errors.
-    // We also won't want to continue with errors from rvalue promotion
-    // We only do so if the only error found so far *isn't* a missing `fn main()`
-    if !(entry_point.is_none() && sess.err_count() == 1) {
-        tcx.sess.abort_if_errors();
-    }
-
    time(sess, "borrow checking", || {
        if tcx.use_ast_borrowck() {
            borrowck::check_crate(tcx);
--- a/src/librustc_mir/hair/pattern/check_match.rs
+++ b/src/librustc_mir/hair/pattern/check_match.rs
@ -603,7 +603,9 @@ fn check_legality_of_move_bindings(
            E0009,
            "cannot bind by-move and by-ref in the same pattern",
        );
-        err.span_label(by_ref_span.unwrap(), "both by-ref and by-move used");
+        if let Some(by_ref_span) = by_ref_span {
+            err.span_label(by_ref_span, "both by-ref and by-move used");
+        }
        for span in span_vec.iter(){
            err.span_label(*span, "by-move pattern here");
        }
--- a/src/librustc_mir/transform/qualify_consts.rs
+++ b/src/librustc_mir/transform/qualify_consts.rs
@ -1502,9 +1502,11 @@ impl MirPass for QualifyAndPromoteConstants {
                                tcx.sess,
                                span,
                                E0723,
-                                "{} (see issue #57563)",
+                                "{}",
                                err,
                            );
+                            diag.note("for more information, see issue \
+                                       https://github.com/rust-lang/rust/issues/57563");
                            diag.help(
                                "add #![feature(const_fn)] to the crate attributes to enable",
                            );
--- a/src/test/ui/borrowck/borrowck-mutate-in-guard.rs
+++ b/src/test/ui/borrowck/borrowck-mutate-in-guard.rs
@ -9,9 +9,15 @@ fn foo() -> isize {
    match x {
        Enum::A(_) if { x = Enum::B(false); false } => 1,
        //~^ ERROR cannot assign in a pattern guard
+        //~| WARN cannot assign `x` in match guard
+        //~| WARN this error has been downgraded to a warning for backwards compatibility
+        //~| WARN this represents potential undefined behavior in your code and this warning will
        Enum::A(_) if { let y = &mut x; *y = Enum::B(false); false } => 1,
        //~^ ERROR cannot mutably borrow in a pattern guard
-        //~^^ ERROR cannot assign in a pattern guard
+        //~| ERROR cannot assign in a pattern guard
+        //~| WARN cannot mutably borrow `x` in match guard
+        //~| WARN this error has been downgraded to a warning for backwards compatibility
+        //~| WARN this represents potential undefined behavior in your code and this warning will
        Enum::A(p) => *p,
        Enum::B(_) => 2,
    }
--- a/src/test/ui/borrowck/borrowck-mutate-in-guard.stderr
+++ b/src/test/ui/borrowck/borrowck-mutate-in-guard.stderr
@ -5,7 +5,7 @@ LL |         Enum::A(_) if { x = Enum::B(false); false } => 1,
   |                         ^^^^^^^^^^^^^^^^^^ assignment in pattern guard

 error[E0301]: cannot mutably borrow in a pattern guard
-  --> $DIR/borrowck-mutate-in-guard.rs:12:38
+  --> $DIR/borrowck-mutate-in-guard.rs:15:38
   |
 LL |         Enum::A(_) if { let y = &mut x; *y = Enum::B(false); false } => 1,
   |                                      ^ borrowed mutably in pattern guard
@ -13,12 +13,35 @@ LL |         Enum::A(_) if { let y = &mut x; *y = Enum::B(false); false } => 1,
   = help: add #![feature(bind_by_move_pattern_guards)] to the crate attributes to enable

 error[E0302]: cannot assign in a pattern guard
-  --> $DIR/borrowck-mutate-in-guard.rs:12:41
+  --> $DIR/borrowck-mutate-in-guard.rs:15:41
   |
 LL |         Enum::A(_) if { let y = &mut x; *y = Enum::B(false); false } => 1,
   |                                         ^^^^^^^^^^^^^^^^^^^ assignment in pattern guard

+warning[E0510]: cannot assign `x` in match guard
+  --> $DIR/borrowck-mutate-in-guard.rs:10:25
+   |
+LL |     match x {
+   |           - value is immutable in match guard
+LL |         Enum::A(_) if { x = Enum::B(false); false } => 1,
+   |                         ^^^^^^^^^^^^^^^^^^ cannot assign
+   |
+   = warning: this error has been downgraded to a warning for backwards compatibility with previous releases
+   = warning: this represents potential undefined behavior in your code and this warning will become a hard error in the future
+
+warning[E0510]: cannot mutably borrow `x` in match guard
+  --> $DIR/borrowck-mutate-in-guard.rs:15:33
+   |
+LL |     match x {
+   |           - value is immutable in match guard
+...
+LL |         Enum::A(_) if { let y = &mut x; *y = Enum::B(false); false } => 1,
+   |                                 ^^^^^^ cannot mutably borrow
+   |
+   = warning: this error has been downgraded to a warning for backwards compatibility with previous releases
+   = warning: this represents potential undefined behavior in your code and this warning will become a hard error in the future
+
 error: aborting due to 3 previous errors

-Some errors have detailed explanations: E0301, E0302.
+Some errors have detailed explanations: E0301, E0302, E0510.
 For more information about an error, try `rustc --explain E0301`.
--- a/src/test/ui/consts/const_let_refutable.rs
+++ b/src/test/ui/consts/const_let_refutable.rs
@ -1,5 +1,11 @@
 fn main() {}

 const fn slice([a, b]: &[i32]) -> i32 { //~ ERROR refutable pattern in function argument
-    a + b
+    a + b //~ ERROR can only call other `const fn` within a `const fn`
+    //~^ WARN use of possibly uninitialized variable: `a`
+    //~| WARN this error has been downgraded to a warning for backwards compatibility
+    //~| WARN this represents potential undefined behavior in your code and this warning will
+    //~| WARN use of possibly uninitialized variable: `b`
+    //~| WARN this error has been downgraded to a warning for backwards compatibility
+    //~| WARN this represents potential undefined behavior in your code and this warning will
 }
--- a/src/test/ui/consts/const_let_refutable.stderr
+++ b/src/test/ui/consts/const_let_refutable.stderr
@ -4,6 +4,34 @@ error[E0005]: refutable pattern in function argument: `&[]` not covered
 LL | const fn slice([a, b]: &[i32]) -> i32 {
   |                ^^^^^^ pattern `&[]` not covered

-error: aborting due to previous error
+error[E0723]: can only call other `const fn` within a `const fn`, but `const std::ops::Add::add` is not stable as `const fn`
+  --> $DIR/const_let_refutable.rs:4:5
+   |
+LL |     a + b
+   |     ^^^^^
+   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
+   = help: add #![feature(const_fn)] to the crate attributes to enable

-For more information about this error, try `rustc --explain E0005`.
+warning[E0381]: use of possibly uninitialized variable: `a`
+  --> $DIR/const_let_refutable.rs:4:5
+   |
+LL |     a + b
+   |     ^ use of possibly uninitialized `a`
+   |
+   = warning: this error has been downgraded to a warning for backwards compatibility with previous releases
+   = warning: this represents potential undefined behavior in your code and this warning will become a hard error in the future
+
+warning[E0381]: use of possibly uninitialized variable: `b`
+  --> $DIR/const_let_refutable.rs:4:9
+   |
+LL |     a + b
+   |         ^ use of possibly uninitialized `b`
+   |
+   = warning: this error has been downgraded to a warning for backwards compatibility with previous releases
+   = warning: this represents potential undefined behavior in your code and this warning will become a hard error in the future
+
+error: aborting due to 2 previous errors
+
+Some errors have detailed explanations: E0005, E0381, E0723.
+For more information about an error, try `rustc --explain E0005`.
--- a/src/test/ui/consts/match_ice.stderr
+++ b/src/test/ui/consts/match_ice.stderr
@ -1,11 +1,17 @@
 error[E0004]: non-exhaustive patterns: `&S` not covered
-  --> $DIR/match_ice.rs:7:11
+  --> $DIR/match_ice.rs:8:11
   |
 LL |     match C {
   |           ^ pattern `&S` not covered
   |
   = help: ensure that all possible cases are being handled, possibly by adding wildcards or more match arms

-error: aborting due to previous error
+error[E0277]: can't compare `S` with `S`
+   |
+   = help: the trait `std::cmp::PartialEq` is not implemented for `S`
+   = note: required because of the requirements on the impl of `std::cmp::PartialEq` for `&S`

-For more information about this error, try `rustc --explain E0004`.
+error: aborting due to 2 previous errors
+
+Some errors occurred: E0004, E0277.
+For more information about an error, try `rustc --explain E0004`.
--- a/src/test/ui/consts/min_const_fn/bad_const_fn_body_ice.stderr
+++ b/src/test/ui/consts/min_const_fn/bad_const_fn_body_ice.stderr
@ -1,9 +1,10 @@
-error[E0723]: heap allocations are not allowed in const fn (see issue #57563)
+error[E0723]: heap allocations are not allowed in const fn
  --> $DIR/bad_const_fn_body_ice.rs:2:5
   |
 LL |     vec![1, 2, 3]
   |     ^^^^^^^^^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable
   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)

--- a/src/test/ui/consts/min_const_fn/cast_errors.stderr
+++ b/src/test/ui/consts/min_const_fn/cast_errors.stderr
@ -1,41 +1,46 @@
-error[E0723]: unsizing casts are not allowed in const fn (see issue #57563)
+error[E0723]: unsizing casts are not allowed in const fn
  --> $DIR/cast_errors.rs:3:41
   |
 LL | const fn unsize(x: &[u8; 3]) -> &[u8] { x }
   |                                         ^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: function pointers in const fn are unstable (see issue #57563)
+error[E0723]: function pointers in const fn are unstable
  --> $DIR/cast_errors.rs:5:23
   |
 LL | const fn closure() -> fn() { || {} }
   |                       ^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: function pointers in const fn are unstable (see issue #57563)
+error[E0723]: function pointers in const fn are unstable
  --> $DIR/cast_errors.rs:8:5
   |
 LL |     (|| {}) as fn();
   |     ^^^^^^^^^^^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: function pointers in const fn are unstable (see issue #57563)
+error[E0723]: function pointers in const fn are unstable
  --> $DIR/cast_errors.rs:11:28
   |
 LL | const fn reify(f: fn()) -> unsafe fn() { f }
   |                            ^^^^^^^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: function pointers in const fn are unstable (see issue #57563)
+error[E0723]: function pointers in const fn are unstable
  --> $DIR/cast_errors.rs:13:21
   |
 LL | const fn reify2() { main as unsafe fn(); }
   |                     ^^^^^^^^^^^^^^^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

 error: aborting due to 5 previous errors
--- a/src/test/ui/consts/min_const_fn/cmp_fn_pointers.stderr
+++ b/src/test/ui/consts/min_const_fn/cmp_fn_pointers.stderr
@ -1,9 +1,10 @@
-error[E0723]: function pointers in const fn are unstable (see issue #57563)
+error[E0723]: function pointers in const fn are unstable
  --> $DIR/cmp_fn_pointers.rs:1:14
   |
 LL | const fn cmp(x: fn(), y: fn()) -> bool {
   |              ^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

 error: aborting due to previous error
--- a/src/test/ui/consts/min_const_fn/loop_ice.stderr
+++ b/src/test/ui/consts/min_const_fn/loop_ice.stderr
@ -1,9 +1,10 @@
-error[E0723]: loops are not allowed in const fn (see issue #57563)
+error[E0723]: loops are not allowed in const fn
  --> $DIR/loop_ice.rs:2:5
   |
 LL |     loop {}
   |     ^^^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

 error: aborting due to previous error
--- a/src/test/ui/consts/min_const_fn/min_const_fn.stderr
+++ b/src/test/ui/consts/min_const_fn/min_const_fn.stderr
@ -4,12 +4,13 @@ error[E0493]: destructors cannot be evaluated at compile-time
 LL |     const fn into_inner(self) -> T { self.0 }
   |                         ^^^^ constant functions cannot evaluate destructors

-error[E0723]: mutable references in const fn are unstable (see issue #57563)
+error[E0723]: mutable references in const fn are unstable
  --> $DIR/min_const_fn.rs:39:36
   |
 LL |     const fn get_mut(&mut self) -> &mut T { &mut self.0 }
   |                                    ^^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

 error[E0493]: destructors cannot be evaluated at compile-time
@ -18,12 +19,13 @@ error[E0493]: destructors cannot be evaluated at compile-time
 LL |     const fn into_inner_lt(self) -> T { self.0 }
   |                            ^^^^ constant functions cannot evaluate destructors

-error[E0723]: mutable references in const fn are unstable (see issue #57563)
+error[E0723]: mutable references in const fn are unstable
  --> $DIR/min_const_fn.rs:46:42
   |
 LL |     const fn get_mut_lt(&'a mut self) -> &mut T { &mut self.0 }
   |                                          ^^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

 error[E0493]: destructors cannot be evaluated at compile-time
@ -32,228 +34,256 @@ error[E0493]: destructors cannot be evaluated at compile-time
 LL |     const fn into_inner_s(self) -> T { self.0 }
   |                           ^^^^ constant functions cannot evaluate destructors

-error[E0723]: mutable references in const fn are unstable (see issue #57563)
+error[E0723]: mutable references in const fn are unstable
  --> $DIR/min_const_fn.rs:53:38
   |
 LL |     const fn get_mut_s(&mut self) -> &mut T { &mut self.0 }
   |                                      ^^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: mutable references in const fn are unstable (see issue #57563)
+error[E0723]: mutable references in const fn are unstable
  --> $DIR/min_const_fn.rs:58:39
   |
 LL |     const fn get_mut_sq(&mut self) -> &mut T { &mut self.0 }
   |                                       ^^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable (see issue #57563)
+error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable
  --> $DIR/min_const_fn.rs:76:16
   |
 LL | const fn foo11<T: std::fmt::Display>(t: T) -> T { t }
   |                ^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable (see issue #57563)
+error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable
  --> $DIR/min_const_fn.rs:78:18
   |
 LL | const fn foo11_2<T: Send>(t: T) -> T { t }
   |                  ^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: only int, `bool` and `char` operations are stable in const fn (see issue #57563)
+error[E0723]: only int, `bool` and `char` operations are stable in const fn
  --> $DIR/min_const_fn.rs:80:33
   |
 LL | const fn foo19(f: f32) -> f32 { f * 2.0 }
   |                                 ^^^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: only int, `bool` and `char` operations are stable in const fn (see issue #57563)
+error[E0723]: only int, `bool` and `char` operations are stable in const fn
  --> $DIR/min_const_fn.rs:82:35
   |
 LL | const fn foo19_2(f: f32) -> f32 { 2.0 - f }
   |                                   ^^^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: only int and `bool` operations are stable in const fn (see issue #57563)
+error[E0723]: only int and `bool` operations are stable in const fn
  --> $DIR/min_const_fn.rs:84:35
   |
 LL | const fn foo19_3(f: f32) -> f32 { -f }
   |                                   ^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: only int, `bool` and `char` operations are stable in const fn (see issue #57563)
+error[E0723]: only int, `bool` and `char` operations are stable in const fn
  --> $DIR/min_const_fn.rs:86:43
   |
 LL | const fn foo19_4(f: f32, g: f32) -> f32 { f / g }
   |                                           ^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: cannot access `static` items in const fn (see issue #57563)
+error[E0723]: cannot access `static` items in const fn
  --> $DIR/min_const_fn.rs:90:27
   |
 LL | const fn foo25() -> u32 { BAR }
   |                           ^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: cannot access `static` items in const fn (see issue #57563)
+error[E0723]: cannot access `static` items in const fn
  --> $DIR/min_const_fn.rs:91:36
   |
 LL | const fn foo26() -> &'static u32 { &BAR }
   |                                    ^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: casting pointers to ints is unstable in const fn (see issue #57563)
+error[E0723]: casting pointers to ints is unstable in const fn
  --> $DIR/min_const_fn.rs:92:42
   |
 LL | const fn foo30(x: *const u32) -> usize { x as usize }
   |                                          ^^^^^^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: casting pointers to ints is unstable in const fn (see issue #57563)
+error[E0723]: casting pointers to ints is unstable in const fn
  --> $DIR/min_const_fn.rs:94:63
   |
 LL | const fn foo30_with_unsafe(x: *const u32) -> usize { unsafe { x as usize } }
   |                                                               ^^^^^^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: casting pointers to ints is unstable in const fn (see issue #57563)
+error[E0723]: casting pointers to ints is unstable in const fn
  --> $DIR/min_const_fn.rs:96:42
   |
 LL | const fn foo30_2(x: *mut u32) -> usize { x as usize }
   |                                          ^^^^^^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: casting pointers to ints is unstable in const fn (see issue #57563)
+error[E0723]: casting pointers to ints is unstable in const fn
  --> $DIR/min_const_fn.rs:98:63
   |
 LL | const fn foo30_2_with_unsafe(x: *mut u32) -> usize { unsafe { x as usize } }
   |                                                               ^^^^^^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: `if`, `match`, `&&` and `||` are not stable in const fn (see issue #57563)
+error[E0723]: `if`, `match`, `&&` and `||` are not stable in const fn
  --> $DIR/min_const_fn.rs:100:38
   |
 LL | const fn foo30_4(b: bool) -> usize { if b { 1 } else { 42 } }
   |                                      ^^^^^^^^^^^^^^^^^^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: `if`, `match`, `&&` and `||` are not stable in const fn (see issue #57563)
+error[E0723]: `if`, `match`, `&&` and `||` are not stable in const fn
  --> $DIR/min_const_fn.rs:102:29
   |
 LL | const fn foo30_5(b: bool) { while b { } }
   |                             ^^^^^^^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: `if`, `match`, `&&` and `||` are not stable in const fn (see issue #57563)
+error[E0723]: `if`, `match`, `&&` and `||` are not stable in const fn
  --> $DIR/min_const_fn.rs:104:44
   |
 LL | const fn foo36(a: bool, b: bool) -> bool { a && b }
   |                                            ^^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: `if`, `match`, `&&` and `||` are not stable in const fn (see issue #57563)
+error[E0723]: `if`, `match`, `&&` and `||` are not stable in const fn
  --> $DIR/min_const_fn.rs:106:44
   |
 LL | const fn foo37(a: bool, b: bool) -> bool { a || b }
   |                                            ^^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: mutable references in const fn are unstable (see issue #57563)
+error[E0723]: mutable references in const fn are unstable
  --> $DIR/min_const_fn.rs:108:14
   |
 LL | const fn inc(x: &mut i32) { *x += 1 }
   |              ^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable (see issue #57563)
+error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable
  --> $DIR/min_const_fn.rs:113:6
   |
 LL | impl<T: std::fmt::Debug> Foo<T> {
   |      ^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable (see issue #57563)
+error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable
  --> $DIR/min_const_fn.rs:118:6
   |
 LL | impl<T: std::fmt::Debug + Sized> Foo<T> {
   |      ^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable (see issue #57563)
+error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable
  --> $DIR/min_const_fn.rs:123:6
   |
 LL | impl<T: Sync + Sized> Foo<T> {
   |      ^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: `impl Trait` in const fn is unstable (see issue #57563)
+error[E0723]: `impl Trait` in const fn is unstable
  --> $DIR/min_const_fn.rs:129:24
   |
 LL | const fn no_rpit2() -> AlanTuring<impl std::fmt::Debug> { AlanTuring(0) }
   |                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable (see issue #57563)
+error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable
  --> $DIR/min_const_fn.rs:131:34
   |
 LL | const fn no_apit2(_x: AlanTuring<impl std::fmt::Debug>) {}
   |                                  ^^^^^^^^^^^^^^^^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable (see issue #57563)
+error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable
  --> $DIR/min_const_fn.rs:133:22
   |
 LL | const fn no_apit(_x: impl std::fmt::Debug) {}
   |                      ^^^^^^^^^^^^^^^^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: `impl Trait` in const fn is unstable (see issue #57563)
+error[E0723]: `impl Trait` in const fn is unstable
  --> $DIR/min_const_fn.rs:134:23
   |
 LL | const fn no_rpit() -> impl std::fmt::Debug {}
   |                       ^^^^^^^^^^^^^^^^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable (see issue #57563)
+error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable
  --> $DIR/min_const_fn.rs:135:23
   |
 LL | const fn no_dyn_trait(_x: &dyn std::fmt::Debug) {}
   |                       ^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable (see issue #57563)
+error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable
  --> $DIR/min_const_fn.rs:136:32
   |
 LL | const fn no_dyn_trait_ret() -> &'static dyn std::fmt::Debug { &() }
   |                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

 warning[E0515]: cannot return reference to temporary value
@ -268,28 +298,31 @@ LL | const fn no_dyn_trait_ret() -> &'static dyn std::fmt::Debug { &() }
   = warning: this error has been downgraded to a warning for backwards compatibility with previous releases
   = warning: this represents potential undefined behavior in your code and this warning will become a hard error in the future

-error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable (see issue #57563)
+error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable
  --> $DIR/min_const_fn.rs:144:41
   |
 LL | const fn really_no_traits_i_mean_it() { (&() as &std::fmt::Debug, ()).1 }
   |                                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: function pointers in const fn are unstable (see issue #57563)
+error[E0723]: function pointers in const fn are unstable
  --> $DIR/min_const_fn.rs:147:21
   |
 LL | const fn no_fn_ptrs(_x: fn()) {}
   |                     ^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: function pointers in const fn are unstable (see issue #57563)
+error[E0723]: function pointers in const fn are unstable
  --> $DIR/min_const_fn.rs:149:27
   |
 LL | const fn no_fn_ptrs2() -> fn() { fn foo() {} foo }
   |                           ^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

 error: aborting due to 36 previous errors
--- a/src/test/ui/consts/min_const_fn/min_const_fn_dyn.stderr
+++ b/src/test/ui/consts/min_const_fn/min_const_fn_dyn.stderr
@ -1,17 +1,19 @@
-error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable (see issue #57563)
+error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable
  --> $DIR/min_const_fn_dyn.rs:9:5
   |
 LL |     x.0.field;
   |     ^^^^^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable (see issue #57563)
+error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable
  --> $DIR/min_const_fn_dyn.rs:12:66
   |
 LL | const fn no_inner_dyn_trait_ret() -> Hide { Hide(HasDyn { field: &0 }) }
   |                                                                  ^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

 warning[E0716]: temporary value dropped while borrowed
--- a/src/test/ui/consts/min_const_fn/min_const_fn_fn_ptr.stderr
+++ b/src/test/ui/consts/min_const_fn/min_const_fn_fn_ptr.stderr
@ -1,17 +1,19 @@
-error[E0723]: function pointers in const fn are unstable (see issue #57563)
+error[E0723]: function pointers in const fn are unstable
  --> $DIR/min_const_fn_fn_ptr.rs:11:5
   |
 LL |     x.0.field;
   |     ^^^^^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: function pointers in const fn are unstable (see issue #57563)
+error[E0723]: function pointers in const fn are unstable
  --> $DIR/min_const_fn_fn_ptr.rs:14:59
   |
 LL | const fn no_inner_dyn_trait_ret() -> Hide { Hide(HasPtr { field }) }
   |                                                           ^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

 error: aborting due to 2 previous errors
--- a/src/test/ui/consts/min_const_fn/min_const_fn_libstd_stability.stderr
+++ b/src/test/ui/consts/min_const_fn/min_const_fn_libstd_stability.stderr
@ -1,33 +1,37 @@
-error[E0723]: can only call other `const fn` within a `const fn`, but `const foo` is not stable as `const fn` (see issue #57563)
+error[E0723]: can only call other `const fn` within a `const fn`, but `const foo` is not stable as `const fn`
  --> $DIR/min_const_fn_libstd_stability.rs:15:25
   |
 LL | const fn bar() -> u32 { foo() }
   |                         ^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: can only call other `const fn` within a `const fn`, but `const foo2` is not stable as `const fn` (see issue #57563)
+error[E0723]: can only call other `const fn` within a `const fn`, but `const foo2` is not stable as `const fn`
  --> $DIR/min_const_fn_libstd_stability.rs:22:26
   |
 LL | const fn bar2() -> u32 { foo2() }
   |                          ^^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: only int, `bool` and `char` operations are stable in const fn (see issue #57563)
+error[E0723]: only int, `bool` and `char` operations are stable in const fn
  --> $DIR/min_const_fn_libstd_stability.rs:26:26
   |
 LL | const fn bar3() -> u32 { (5f32 + 6f32) as u32 }
   |                          ^^^^^^^^^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: can only call other `const fn` within a `const fn`, but `const foo2_gated` is not stable as `const fn` (see issue #57563)
+error[E0723]: can only call other `const fn` within a `const fn`, but `const foo2_gated` is not stable as `const fn`
  --> $DIR/min_const_fn_libstd_stability.rs:34:32
   |
 LL | const fn bar2_gated() -> u32 { foo2_gated() }
   |                                ^^^^^^^^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

 error: aborting due to 4 previous errors
--- a/src/test/ui/consts/min_const_fn/min_const_unsafe_fn_libstd_stability.stderr
+++ b/src/test/ui/consts/min_const_fn/min_const_unsafe_fn_libstd_stability.stderr
@ -1,33 +1,37 @@
-error[E0723]: can only call other `const fn` within a `const fn`, but `const foo` is not stable as `const fn` (see issue #57563)
+error[E0723]: can only call other `const fn` within a `const fn`, but `const foo` is not stable as `const fn`
  --> $DIR/min_const_unsafe_fn_libstd_stability.rs:15:41
   |
 LL | const unsafe fn bar() -> u32 { unsafe { foo() } }
   |                                         ^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: can only call other `const fn` within a `const fn`, but `const foo2` is not stable as `const fn` (see issue #57563)
+error[E0723]: can only call other `const fn` within a `const fn`, but `const foo2` is not stable as `const fn`
  --> $DIR/min_const_unsafe_fn_libstd_stability.rs:22:42
   |
 LL | const unsafe fn bar2() -> u32 { unsafe { foo2() } }
   |                                          ^^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: only int, `bool` and `char` operations are stable in const fn (see issue #57563)
+error[E0723]: only int, `bool` and `char` operations are stable in const fn
  --> $DIR/min_const_unsafe_fn_libstd_stability.rs:26:33
   |
 LL | const unsafe fn bar3() -> u32 { (5f32 + 6f32) as u32 }
   |                                 ^^^^^^^^^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: can only call other `const fn` within a `const fn`, but `const foo2_gated` is not stable as `const fn` (see issue #57563)
+error[E0723]: can only call other `const fn` within a `const fn`, but `const foo2_gated` is not stable as `const fn`
  --> $DIR/min_const_unsafe_fn_libstd_stability.rs:34:48
   |
 LL | const unsafe fn bar2_gated() -> u32 { unsafe { foo2_gated() } }
   |                                                ^^^^^^^^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

 error: aborting due to 4 previous errors
--- a/src/test/ui/consts/min_const_fn/min_const_unsafe_fn_libstd_stability2.stderr
+++ b/src/test/ui/consts/min_const_fn/min_const_unsafe_fn_libstd_stability2.stderr
@ -1,25 +1,28 @@
-error[E0723]: can only call other `const fn` within a `const fn`, but `const foo` is not stable as `const fn` (see issue #57563)
+error[E0723]: can only call other `const fn` within a `const fn`, but `const foo` is not stable as `const fn`
  --> $DIR/min_const_unsafe_fn_libstd_stability2.rs:15:32
   |
 LL | const unsafe fn bar() -> u32 { foo() }
   |                                ^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: can only call other `const fn` within a `const fn`, but `const foo2` is not stable as `const fn` (see issue #57563)
+error[E0723]: can only call other `const fn` within a `const fn`, but `const foo2` is not stable as `const fn`
  --> $DIR/min_const_unsafe_fn_libstd_stability2.rs:22:33
   |
 LL | const unsafe fn bar2() -> u32 { foo2() }
   |                                 ^^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: can only call other `const fn` within a `const fn`, but `const foo2_gated` is not stable as `const fn` (see issue #57563)
+error[E0723]: can only call other `const fn` within a `const fn`, but `const foo2_gated` is not stable as `const fn`
  --> $DIR/min_const_unsafe_fn_libstd_stability2.rs:30:39
   |
 LL | const unsafe fn bar2_gated() -> u32 { foo2_gated() }
   |                                       ^^^^^^^^^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

 error: aborting due to 3 previous errors
--- a/src/test/ui/consts/min_const_fn/mutable_borrow.stderr
+++ b/src/test/ui/consts/min_const_fn/mutable_borrow.stderr
@ -1,17 +1,19 @@
-error[E0723]: mutable references in const fn are unstable (see issue #57563)
+error[E0723]: mutable references in const fn are unstable
  --> $DIR/mutable_borrow.rs:3:9
   |
 LL |     let b = &mut a;
   |         ^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: mutable references in const fn are unstable (see issue #57563)
+error[E0723]: mutable references in const fn are unstable
  --> $DIR/mutable_borrow.rs:12:13
   |
 LL |         let b = &mut a;
   |             ^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

 error: aborting due to 2 previous errors
--- a/src/test/ui/consts/single_variant_match_ice.stderr
+++ b/src/test/ui/consts/single_variant_match_ice.stderr
@ -10,12 +10,13 @@ error[E0019]: constant contains unimplemented expression type
 LL |     x => 42,
   |     ^

-error[E0723]: `if`, `match`, `&&` and `||` are not stable in const fn (see issue #57563)
+error[E0723]: `if`, `match`, `&&` and `||` are not stable in const fn
  --> $DIR/single_variant_match_ice.rs:18:13
   |
 LL |             Prob => 0x1,
   |             ^^^^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

 error: aborting due to 3 previous errors
--- a/src/test/ui/empty/empty-never-array.rs
+++ b/src/test/ui/empty/empty-never-array.rs
@ -10,6 +10,9 @@ fn transmute<T, U>(t: T) -> U {
    let Helper::U(u) = Helper::T(t, []);
    //~^ ERROR refutable pattern in local binding: `T(_, _)` not covered
    u
+    //~^ WARN use of possibly uninitialized variable: `u`
+    //~| WARN this error has been downgraded to a warning for backwards compatibility
+    //~| WARN this represents potential undefined behavior in your code and this warning will
 }

 fn main() {
--- a/src/test/ui/empty/empty-never-array.stderr
+++ b/src/test/ui/empty/empty-never-array.stderr
@ -11,6 +11,16 @@ LL | | }
 LL |       let Helper::U(u) = Helper::T(t, []);
   |           ^^^^^^^^^^^^ pattern `T(_, _)` not covered

+warning[E0381]: use of possibly uninitialized variable: `u`
+  --> $DIR/empty-never-array.rs:12:5
+   |
+LL |     u
+   |     ^ use of possibly uninitialized `u`
+   |
+   = warning: this error has been downgraded to a warning for backwards compatibility with previous releases
+   = warning: this represents potential undefined behavior in your code and this warning will become a hard error in the future
+
 error: aborting due to previous error

-For more information about this error, try `rustc --explain E0005`.
+Some errors have detailed explanations: E0005, E0381.
+For more information about an error, try `rustc --explain E0005`.
--- a/src/test/ui/error-codes/E0007.rs
+++ b/src/test/ui/error-codes/E0007.rs
@ -4,6 +4,7 @@ fn main() {
        op_string @ Some(s) => {},
        //~^ ERROR E0007
        //~| ERROR E0303
+        //~| ERROR E0382
        None => {},
    }
 }
--- a/src/test/ui/error-codes/E0007.stderr
+++ b/src/test/ui/error-codes/E0007.stderr
@ -10,7 +10,19 @@ error[E0303]: pattern bindings are not allowed after an `@`
 LL |         op_string @ Some(s) => {},
   |                          ^ not allowed after `@`

-error: aborting due to 2 previous errors
+error[E0382]: use of moved value
+  --> $DIR/E0007.rs:4:26
+   |
+LL |     let x = Some("s".to_string());
+   |         - move occurs because `x` has type `std::option::Option<std::string::String>`, which does not implement the `Copy` trait
+LL |     match x {
+LL |         op_string @ Some(s) => {},
+   |         -----------------^-
+   |         |                |
+   |         |                value used here after move
+   |         value moved here

-Some errors have detailed explanations: E0007, E0303.
+error: aborting due to 3 previous errors
+
+Some errors have detailed explanations: E0007, E0303, E0382.
 For more information about an error, try `rustc --explain E0007`.
--- a/src/test/ui/error-codes/E0030-teach.rs
+++ b/src/test/ui/error-codes/E0030-teach.rs
@ -4,5 +4,6 @@ fn main() {
    match 5u32 {
        1000 ..= 5 => {}
        //~^ ERROR lower range bound must be less than or equal to upper
+        //~| ERROR lower range bound must be less than or equal to upper
    }
 }
--- a/src/test/ui/error-codes/E0030-teach.stderr
+++ b/src/test/ui/error-codes/E0030-teach.stderr
@ -6,6 +6,12 @@ LL |         1000 ..= 5 => {}
   |
   = note: When matching against a range, the compiler verifies that the range is non-empty. Range patterns include both end-points, so this is equivalent to requiring the start of the range to be less than or equal to the end of the range.

-error: aborting due to previous error
+error[E0030]: lower range bound must be less than or equal to upper
+  --> $DIR/E0030-teach.rs:5:9
+   |
+LL |         1000 ..= 5 => {}
+   |         ^^^^ lower bound larger than upper bound
+
+error: aborting due to 2 previous errors

 For more information about this error, try `rustc --explain E0030`.
--- a/src/test/ui/error-codes/E0301.rs
+++ b/src/test/ui/error-codes/E0301.rs
@ -2,6 +2,6 @@ fn main() {
    match Some(()) {
        None => { },
        option if option.take().is_none() => {}, //~ ERROR E0301
-        Some(_) => { }
+        Some(_) => { } //~^ ERROR E0596
    }
 }
--- a/src/test/ui/error-codes/E0301.stderr
+++ b/src/test/ui/error-codes/E0301.stderr
@ -6,6 +6,15 @@ LL |         option if option.take().is_none() => {},
   |
   = help: add #![feature(bind_by_move_pattern_guards)] to the crate attributes to enable

-error: aborting due to previous error
+error[E0596]: cannot borrow `option` as mutable, as it is immutable for the pattern guard
+  --> $DIR/E0301.rs:4:19
+   |
+LL |         option if option.take().is_none() => {},
+   |                   ^^^^^^ cannot borrow as mutable
+   |
+   = note: variables bound in patterns are immutable until the end of the pattern guard

-For more information about this error, try `rustc --explain E0301`.
+error: aborting due to 2 previous errors
+
+Some errors have detailed explanations: E0301, E0596.
+For more information about an error, try `rustc --explain E0301`.
--- a/src/test/ui/error-codes/E0302.rs
+++ b/src/test/ui/error-codes/E0302.rs
@ -2,6 +2,7 @@ fn main() {
    match Some(()) {
        None => { },
        option if { option = None; false } => { }, //~ ERROR E0302
+        //~^ ERROR cannot assign to `option`, as it is immutable for the pattern guard
        Some(_) => { }
    }
 }
--- a/src/test/ui/error-codes/E0302.stderr
+++ b/src/test/ui/error-codes/E0302.stderr
@ -4,6 +4,14 @@ error[E0302]: cannot assign in a pattern guard
 LL |         option if { option = None; false } => { },
   |                     ^^^^^^^^^^^^^ assignment in pattern guard

-error: aborting due to previous error
+error[E0594]: cannot assign to `option`, as it is immutable for the pattern guard
+  --> $DIR/E0302.rs:4:21
+   |
+LL |         option if { option = None; false } => { },
+   |                     ^^^^^^^^^^^^^ cannot assign
+   |
+   = note: variables bound in patterns are immutable until the end of the pattern guard
+
+error: aborting due to 2 previous errors

 For more information about this error, try `rustc --explain E0302`.
--- a/src/test/ui/issues/issue-15381.rs
+++ b/src/test/ui/issues/issue-15381.rs
@ -4,5 +4,8 @@ fn main() {
    for &[x,y,z] in values.chunks(3).filter(|&xs| xs.len() == 3) {
        //~^ ERROR refutable pattern in `for` loop binding: `&[]` not covered
        println!("y={}", y);
+        //~^ WARN borrow of possibly uninitialized variable: `y`
+        //~| WARN this error has been downgraded to a warning for backwards compatibility
+        //~| WARN this represents potential undefined behavior in your code and this warning will
    }
 }
--- a/src/test/ui/issues/issue-15381.stderr
+++ b/src/test/ui/issues/issue-15381.stderr
@ -4,6 +4,16 @@ error[E0005]: refutable pattern in `for` loop binding: `&[]` not covered
 LL |     for &[x,y,z] in values.chunks(3).filter(|&xs| xs.len() == 3) {
   |         ^^^^^^^^ pattern `&[]` not covered

+warning[E0381]: borrow of possibly uninitialized variable: `y`
+  --> $DIR/issue-15381.rs:6:26
+   |
+LL |         println!("y={}", y);
+   |                          ^ use of possibly uninitialized `y`
+   |
+   = warning: this error has been downgraded to a warning for backwards compatibility with previous releases
+   = warning: this represents potential undefined behavior in your code and this warning will become a hard error in the future
+
 error: aborting due to previous error

-For more information about this error, try `rustc --explain E0005`.
+Some errors have detailed explanations: E0005, E0381.
+For more information about an error, try `rustc --explain E0005`.
--- a/src/test/ui/issues/issue-23302-3.rs
+++ b/src/test/ui/issues/issue-23302-3.rs
@ -1,4 +1,5 @@
 const A: i32 = B; //~ ERROR cycle detected
+//~^ ERROR cycle detected

 const B: i32 = A;

--- a/src/test/ui/issues/issue-23302-3.stderr
+++ b/src/test/ui/issues/issue-23302-3.stderr
@ -10,18 +10,36 @@ note: ...which requires checking which parts of `A` are promotable to static...
 LL | const A: i32 = B;
   |                ^
 note: ...which requires const checking if rvalue is promotable to static `B`...
-  --> $DIR/issue-23302-3.rs:3:1
+  --> $DIR/issue-23302-3.rs:4:1
   |
 LL | const B: i32 = A;
   | ^^^^^^^^^^^^^^^^^
 note: ...which requires checking which parts of `B` are promotable to static...
-  --> $DIR/issue-23302-3.rs:3:16
+  --> $DIR/issue-23302-3.rs:4:16
   |
 LL | const B: i32 = A;
   |                ^
   = note: ...which again requires const checking if rvalue is promotable to static `A`, completing the cycle
   = note: cycle used when running analysis passes on this crate

-error: aborting due to previous error
+error[E0391]: cycle detected when processing `A`
+  --> $DIR/issue-23302-3.rs:1:16
+   |
+LL | const A: i32 = B;
+   |                ^
+   |
+note: ...which requires processing `B`...
+  --> $DIR/issue-23302-3.rs:4:16
+   |
+LL | const B: i32 = A;
+   |                ^
+   = note: ...which again requires processing `A`, completing the cycle
+note: cycle used when processing `A`
+  --> $DIR/issue-23302-3.rs:1:1
+   |
+LL | const A: i32 = B;
+   | ^^^^^^^^^^^^^^^^^
+
+error: aborting due to 2 previous errors

 For more information about this error, try `rustc --explain E0391`.
--- a/src/test/ui/issues/issue-37550.stderr
+++ b/src/test/ui/issues/issue-37550.stderr
@ -1,9 +1,10 @@
-error[E0723]: function pointers in const fn are unstable (see issue #57563)
+error[E0723]: function pointers in const fn are unstable
  --> $DIR/issue-37550.rs:3:9
   |
 LL |     let x = || t;
   |         ^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

 error: aborting due to previous error
--- a/src/test/ui/issues/issue-41255.rs
+++ b/src/test/ui/issues/issue-41255.rs
@ -9,6 +9,8 @@ fn main() {
    match x {
        5.0 => {}, //~ ERROR floating-point types cannot be used in patterns
                   //~| WARNING hard error
+                   //~| ERROR floating-point types cannot be used in patterns
+                   //~| WARNING this was previously accepted by the compiler but is being
        5.0f32 => {}, //~ ERROR floating-point types cannot be used in patterns
                      //~| WARNING hard error
        -5.0 => {}, //~ ERROR floating-point types cannot be used in patterns
--- a/src/test/ui/issues/issue-41255.stderr
+++ b/src/test/ui/issues/issue-41255.stderr
@ -13,7 +13,7 @@ LL | #![forbid(illegal_floating_point_literal_pattern)]
   = note: for more information, see issue #41620 <https://github.com/rust-lang/rust/issues/41620>

 error: floating-point types cannot be used in patterns
-  --> $DIR/issue-41255.rs:12:9
+  --> $DIR/issue-41255.rs:14:9
   |
 LL |         5.0f32 => {},
   |         ^^^^^^
@ -22,7 +22,7 @@ LL |         5.0f32 => {},
   = note: for more information, see issue #41620 <https://github.com/rust-lang/rust/issues/41620>

 error: floating-point types cannot be used in patterns
-  --> $DIR/issue-41255.rs:14:10
+  --> $DIR/issue-41255.rs:16:10
   |
 LL |         -5.0 => {},
   |          ^^^
@ -31,7 +31,7 @@ LL |         -5.0 => {},
   = note: for more information, see issue #41620 <https://github.com/rust-lang/rust/issues/41620>

 error: floating-point types cannot be used in patterns
-  --> $DIR/issue-41255.rs:16:9
+  --> $DIR/issue-41255.rs:18:9
   |
 LL |         1.0 .. 33.0 => {},
   |         ^^^
@ -40,7 +40,7 @@ LL |         1.0 .. 33.0 => {},
   = note: for more information, see issue #41620 <https://github.com/rust-lang/rust/issues/41620>

 error: floating-point types cannot be used in patterns
-  --> $DIR/issue-41255.rs:16:16
+  --> $DIR/issue-41255.rs:18:16
   |
 LL |         1.0 .. 33.0 => {},
   |                ^^^^
@ -49,7 +49,7 @@ LL |         1.0 .. 33.0 => {},
   = note: for more information, see issue #41620 <https://github.com/rust-lang/rust/issues/41620>

 error: floating-point types cannot be used in patterns
-  --> $DIR/issue-41255.rs:20:9
+  --> $DIR/issue-41255.rs:22:9
   |
 LL |         39.0 ..= 70.0 => {},
   |         ^^^^
@ -58,7 +58,7 @@ LL |         39.0 ..= 70.0 => {},
   = note: for more information, see issue #41620 <https://github.com/rust-lang/rust/issues/41620>

 error: floating-point types cannot be used in patterns
-  --> $DIR/issue-41255.rs:20:18
+  --> $DIR/issue-41255.rs:22:18
   |
 LL |         39.0 ..= 70.0 => {},
   |                  ^^^^
@ -67,7 +67,7 @@ LL |         39.0 ..= 70.0 => {},
   = note: for more information, see issue #41620 <https://github.com/rust-lang/rust/issues/41620>

 error: floating-point types cannot be used in patterns
-  --> $DIR/issue-41255.rs:29:10
+  --> $DIR/issue-41255.rs:31:10
   |
 LL |         (3.14, 1) => {},
   |          ^^^^
@ -76,7 +76,7 @@ LL |         (3.14, 1) => {},
   = note: for more information, see issue #41620 <https://github.com/rust-lang/rust/issues/41620>

 error: floating-point types cannot be used in patterns
-  --> $DIR/issue-41255.rs:36:18
+  --> $DIR/issue-41255.rs:38:18
   |
 LL |         Foo { x: 2.0 } => {},
   |                  ^^^
@ -84,5 +84,14 @@ LL |         Foo { x: 2.0 } => {},
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
   = note: for more information, see issue #41620 <https://github.com/rust-lang/rust/issues/41620>

-error: aborting due to 9 previous errors
+error: floating-point types cannot be used in patterns
+  --> $DIR/issue-41255.rs:10:9
+   |
+LL |         5.0 => {},
+   |         ^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #41620 <https://github.com/rust-lang/rust/issues/41620>
+
+error: aborting due to 10 previous errors

--- a/src/test/ui/issues/issue-6804.rs
+++ b/src/test/ui/issues/issue-6804.rs
@ -10,6 +10,8 @@ fn main() {
    match x {
        NAN => {}, //~ ERROR floating-point types cannot be used
        //~^ WARN this was previously accepted by the compiler but is being phased out
+        //~| ERROR floating-point types cannot be used in patterns
+        //~| WARN this was previously accepted by the compiler but is being phased out
        _ => {},
    };

--- a/src/test/ui/issues/issue-6804.stderr
+++ b/src/test/ui/issues/issue-6804.stderr
@ -13,7 +13,7 @@ LL | #![deny(illegal_floating_point_literal_pattern)]
   = note: for more information, see issue #41620 <https://github.com/rust-lang/rust/issues/41620>

 error: floating-point types cannot be used in patterns
-  --> $DIR/issue-6804.rs:17:10
+  --> $DIR/issue-6804.rs:19:10
   |
 LL |         [NAN, _] => {},
   |          ^^^
@ -21,5 +21,14 @@ LL |         [NAN, _] => {},
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
   = note: for more information, see issue #41620 <https://github.com/rust-lang/rust/issues/41620>

-error: aborting due to 2 previous errors
+error: floating-point types cannot be used in patterns
+  --> $DIR/issue-6804.rs:11:9
+   |
+LL |         NAN => {},
+   |         ^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #41620 <https://github.com/rust-lang/rust/issues/41620>
+
+error: aborting due to 3 previous errors

--- a/src/test/ui/match/match-range-fail-dominate.stderr
+++ b/src/test/ui/match/match-range-fail-dominate.stderr
@ -62,5 +62,14 @@ error: unreachable pattern
 LL |       0.02f64 => {}
   |       ^^^^^^^

+warning: floating-point types cannot be used in patterns
+  --> $DIR/match-range-fail-dominate.rs:35:7
+   |
+LL |       0.01f64 ... 6.5f64 => {}
+   |       ^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #41620 <https://github.com/rust-lang/rust/issues/41620>
+
 error: aborting due to 5 previous errors

--- a/src/test/ui/pattern/pattern-bindings-after-at.rs
+++ b/src/test/ui/pattern/pattern-bindings-after-at.rs
@ -7,6 +7,9 @@ fn main() {
    match &mut Some(1) {
        ref mut z @ &mut Some(ref a) => {
        //~^ ERROR pattern bindings are not allowed after an `@`
+        //~| WARN cannot borrow `_` as immutable because it is also borrowed as mutable
+        //~| WARN this error has been downgraded to a warning for backwards compatibility
+        //~| WARN this represents potential undefined behavior in your code and this warning will
            **z = None;
            println!("{}", *a);
        }
--- a/src/test/ui/pattern/pattern-bindings-after-at.stderr
+++ b/src/test/ui/pattern/pattern-bindings-after-at.stderr
@ -4,6 +4,22 @@ error[E0303]: pattern bindings are not allowed after an `@`
 LL |         ref mut z @ &mut Some(ref a) => {
   |                               ^^^^^ not allowed after `@`

+warning[E0502]: cannot borrow `_` as immutable because it is also borrowed as mutable
+  --> $DIR/pattern-bindings-after-at.rs:8:31
+   |
+LL |         ref mut z @ &mut Some(ref a) => {
+   |         ----------------------^^^^^-
+   |         |                     |
+   |         |                     immutable borrow occurs here
+   |         mutable borrow occurs here
+...
+LL |             **z = None;
+   |             ---------- mutable borrow later used here
+   |
+   = warning: this error has been downgraded to a warning for backwards compatibility with previous releases
+   = warning: this represents potential undefined behavior in your code and this warning will become a hard error in the future
+
 error: aborting due to previous error

-For more information about this error, try `rustc --explain E0303`.
+Some errors have detailed explanations: E0303, E0502.
+For more information about an error, try `rustc --explain E0303`.
--- a/src/test/ui/recursion/recursive-types-are-not-uninhabited.rs
+++ b/src/test/ui/recursion/recursive-types-are-not-uninhabited.rs
@ -6,6 +6,9 @@ fn foo(res: Result<u32, &R>) -> u32 {
    let Ok(x) = res;
    //~^ ERROR refutable pattern
    x
+    //~^ WARN use of possibly uninitialized variable: `x`
+    //~| WARN this error has been downgraded to a warning for backwards compatibility
+    //~| WARN this represents potential undefined behavior in your code and this warning will
 }

 fn main() {
--- a/src/test/ui/recursion/recursive-types-are-not-uninhabited.stderr
+++ b/src/test/ui/recursion/recursive-types-are-not-uninhabited.stderr
@ -4,6 +4,16 @@ error[E0005]: refutable pattern in local binding: `Err(_)` not covered
 LL |     let Ok(x) = res;
   |         ^^^^^ pattern `Err(_)` not covered

+warning[E0381]: use of possibly uninitialized variable: `x`
+  --> $DIR/recursive-types-are-not-uninhabited.rs:8:5
+   |
+LL |     x
+   |     ^ use of possibly uninitialized `x`
+   |
+   = warning: this error has been downgraded to a warning for backwards compatibility with previous releases
+   = warning: this represents potential undefined behavior in your code and this warning will become a hard error in the future
+
 error: aborting due to previous error

-For more information about this error, try `rustc --explain E0005`.
+Some errors have detailed explanations: E0005, E0381.
+For more information about an error, try `rustc --explain E0005`.
--- a/src/test/ui/rfc-2005-default-binding-mode/for.rs
+++ b/src/test/ui/rfc-2005-default-binding-mode/for.rs
@ -5,5 +5,6 @@ pub fn main() {
    // The below desugars to &(ref n, mut m).
    for (n, mut m) in &tups {
        //~^ ERROR cannot bind by-move and by-ref in the same pattern
+        //~| ERROR cannot move out of borrowed content
    }
 }
--- a/src/test/ui/rfc-2005-default-binding-mode/for.stderr
+++ b/src/test/ui/rfc-2005-default-binding-mode/for.stderr
@ -6,6 +6,21 @@ LL |     for (n, mut m) in &tups {
   |          |
   |          both by-ref and by-move used

-error: aborting due to previous error
+error[E0507]: cannot move out of borrowed content
+  --> $DIR/for.rs:6:23
+   |
+LL |     for (n, mut m) in &tups {
+   |             -----     ^^^^^ cannot move out of borrowed content
+   |             |
+   |             data moved here
+   |
+note: move occurs because `m` has type `Foo`, which does not implement the `Copy` trait
+  --> $DIR/for.rs:6:13
+   |
+LL |     for (n, mut m) in &tups {
+   |             ^^^^^

-For more information about this error, try `rustc --explain E0009`.
+error: aborting due to 2 previous errors
+
+Some errors have detailed explanations: E0009, E0507.
+For more information about an error, try `rustc --explain E0009`.
--- a/src/test/ui/rfc1445/match-forbidden-without-eq.rs
+++ b/src/test/ui/rfc1445/match-forbidden-without-eq.rs
@ -20,6 +20,8 @@ fn main() {
        f32::INFINITY => { }
        //~^ WARNING floating-point types cannot be used in patterns
        //~| WARNING will become a hard error in a future release
+        //~| WARNING floating-point types cannot be used in patterns
+        //~| WARNING this was previously accepted by the compiler but is being phased out
        _ => { }
    }
 }
--- a/src/test/ui/rfc1445/match-forbidden-without-eq.stderr
+++ b/src/test/ui/rfc1445/match-forbidden-without-eq.stderr
@ -14,5 +14,14 @@ LL |         f32::INFINITY => { }
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
   = note: for more information, see issue #41620 <https://github.com/rust-lang/rust/issues/41620>

+warning: floating-point types cannot be used in patterns
+  --> $DIR/match-forbidden-without-eq.rs:20:9
+   |
+LL |         f32::INFINITY => { }
+   |         ^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #41620 <https://github.com/rust-lang/rust/issues/41620>
+
 error: aborting due to previous error

--- a/src/test/ui/unsafe/ranged_ints2_const.stderr
+++ b/src/test/ui/unsafe/ranged_ints2_const.stderr
@ -1,17 +1,19 @@
-error[E0723]: mutable references in const fn are unstable (see issue #57563)
+error[E0723]: mutable references in const fn are unstable
  --> $DIR/ranged_ints2_const.rs:11:9
   |
 LL |     let y = &mut x.0;
   |         ^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

-error[E0723]: mutable references in const fn are unstable (see issue #57563)
+error[E0723]: mutable references in const fn are unstable
  --> $DIR/ranged_ints2_const.rs:18:9
   |
 LL |     let y = unsafe { &mut x.0 };
   |         ^
   |
+   = note: for more information, see issue https://github.com/rust-lang/rust/issues/57563
   = help: add #![feature(const_fn)] to the crate attributes to enable

 error[E0133]: mutation of layout constrained field is unsafe and requires unsafe function or block