Reword message for non-structural type constant in pattern

Author: estebank

compiler/rustc_mir_build/messages.ftl

@@ -273,8 +273,7 @@ mir_build_non_exhaustive_patterns_type_not_empty = non-exhaustive patterns: type
     .suggestion = ensure that all possible cases are being handled by adding a match arm with a wildcard pattern as shown
     .help = ensure that all possible cases are being handled by adding a match arm with a wildcard pattern
 
-mir_build_non_partial_eq_match =
-    to use a constant of type `{$non_peq_ty}` in a pattern, the type must implement `PartialEq`
+mir_build_non_partial_eq_match = constant of non-structural type `{$non_peq_ty}` in a pattern
     .label = constant of non-structural type
 
 mir_build_pattern_not_covered = refutable pattern in {$origin}

tests/ui/consts/const_in_pattern/issue-65466.rs

@@ -11,7 +11,7 @@ const C: &[O<B>] = &[O::None];
 fn main() {
     let x = O::None;
     match &[x][..] {
-        C => (), //~ERROR: the type must implement `PartialEq`
+        C => (), //~ ERROR constant of non-structural type `&[O<B>]` in a pattern
         _ => (),
     }
 }

tests/ui/consts/const_in_pattern/issue-65466.stderr

@@ -1,4 +1,4 @@
-error: to use a constant of type `&[O<B>]` in a pattern, the type must implement `PartialEq`
+error: constant of non-structural type `&[O<B>]` in a pattern
   --> $DIR/issue-65466.rs:14:9
    |
 LL | const C: &[O<B>] = &[O::None];

tests/ui/consts/const_in_pattern/reject_non_partial_eq.rs

@@ -26,7 +26,7 @@ fn main() {
 
     match None {
         NO_PARTIAL_EQ_NONE => println!("NO_PARTIAL_EQ_NONE"),
-        //~^ ERROR must implement `PartialEq`
+        //~^ ERROR constant of non-structural type `Option<NoPartialEq>` in a pattern
         _ => panic!("whoops"),
     }
 }

tests/ui/consts/const_in_pattern/reject_non_partial_eq.stderr

@@ -1,4 +1,4 @@
-error: to use a constant of type `Option<NoPartialEq>` in a pattern, the type must implement `PartialEq`
+error: constant of non-structural type `Option<NoPartialEq>` in a pattern
   --> $DIR/reject_non_partial_eq.rs:28:9
    |
 LL | const NO_PARTIAL_EQ_NONE: Option<NoPartialEq> = None;

tests/ui/match/issue-72896-non-partial-eq-const.rs

@@ -16,7 +16,7 @@ const CONST_SET: EnumSet<Enum8> = EnumSet { __enumset_underlying: 3 };
 
 fn main() {
     match CONST_SET {
-        CONST_SET => { /* ok */ } //~ERROR: must implement `PartialEq`
+        CONST_SET => { /* ok */ } //~ ERROR constant of non-structural type `EnumSet<Enum8>` in a pattern
         _ => panic!("match fell through?"),
     }
 }

tests/ui/match/issue-72896-non-partial-eq-const.stderr

@@ -1,4 +1,4 @@
-error: to use a constant of type `EnumSet<Enum8>` in a pattern, the type must implement `PartialEq`
+error: constant of non-structural type `EnumSet<Enum8>` in a pattern
   --> $DIR/issue-72896-non-partial-eq-const.rs:19:9
    |
 LL | const CONST_SET: EnumSet<Enum8> = EnumSet { __enumset_underlying: 3 };

tests/ui/rfcs/rfc-1445-restrict-constants-in-patterns/issue-61188-match-slice-forbidden-without-eq.rs

@@ -12,8 +12,7 @@ const A: &[B] = &[];
 
 pub fn main() {
     match &[][..] {
-        A => (),
-        //~^ ERROR must implement `PartialEq`
+        A => (), //~ ERROR constant of non-structural type `&[B]` in a pattern
         _ => (),
     }
 }

tests/ui/rfcs/rfc-1445-restrict-constants-in-patterns/issue-61188-match-slice-forbidden-without-eq.stderr

@@ -1,4 +1,4 @@
-error: to use a constant of type `&[B]` in a pattern, the type must implement `PartialEq`
+error: constant of non-structural type `&[B]` in a pattern
   --> $DIR/issue-61188-match-slice-forbidden-without-eq.rs:15:9
    |
 LL | const A: &[B] = &[];