Talk about unpredictable instead of "not deterministic"

Author: oli-obk

compiler/rustc_mir_build/src/thir/pattern/const_to_pat.rs

@@ -413,8 +413,8 @@ impl<'a, 'tcx> ConstToPat<'a, 'tcx> {
             ty::FnPtr(..) | ty::RawPtr(..) => {
                 if self.include_lint_checks && !self.saw_const_match_error.get() {
                     self.saw_const_match_error.set(true);
-                    let msg = "function pointers and unsized pointers in patterns do not behave \
-                        deterministically. \
+                    let msg = "function pointers and unsized pointers in patterns behave \
+                        unpredictably and should not be relied upon. \
                         See https://github.com/rust-lang/rust/issues/70861 for details.";
                     tcx.struct_span_lint_hir(
                         lint::builtin::POINTER_STRUCTURAL_MATCH,

src/test/ui/issues/issue-44333.rs

@@ -16,9 +16,9 @@ const BAR: Func = bar;
 
 fn main() {
     match test(std::env::consts::ARCH.len()) {
-        FOO => println!("foo"), //~ WARN pointers in patterns do not behave deterministically
+        FOO => println!("foo"), //~ WARN pointers in patterns behave unpredictably
         //~^ WARN will become a hard error
-        BAR => println!("bar"), //~ WARN pointers in patterns do not behave deterministically
+        BAR => println!("bar"), //~ WARN pointers in patterns behave unpredictably
         //~^ WARN will become a hard error
         _ => unreachable!(),
     }

src/test/ui/issues/issue-44333.stderr

@@ -1,4 +1,4 @@
-warning: function pointers and unsized pointers in patterns do not behave deterministically. See https://github.com/rust-lang/rust/issues/70861 for details.
+warning: function pointers and unsized pointers in patterns behave unpredictably and should not be relied upon. See https://github.com/rust-lang/rust/issues/70861 for details.
   --> $DIR/issue-44333.rs:19:9
    |
 LL |         FOO => println!("foo"),
@@ -12,7 +12,7 @@ LL | #![warn(pointer_structural_match)]
    = 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 #62411 <https://github.com/rust-lang/rust/issues/70861>
 
-warning: function pointers and unsized pointers in patterns do not behave deterministically. See https://github.com/rust-lang/rust/issues/70861 for details.
+warning: function pointers and unsized pointers in patterns behave unpredictably and should not be relied upon. See https://github.com/rust-lang/rust/issues/70861 for details.
   --> $DIR/issue-44333.rs:21:9
    |
 LL |         BAR => println!("bar"),

src/test/ui/rfc1445/issue-63479-match-fnptr.rs

@@ -33,7 +33,7 @@ fn main() {
   let s = B(my_fn);
   match s {
     B(TEST) => println!("matched"),
-    //~^ WARN pointers in patterns do not behave deterministically
+     //~^ WARN pointers in patterns behave unpredictably
     //~| WARN this was previously accepted by the compiler but is being phased out
     _ => panic!("didn't match")
   };

src/test/ui/rfc1445/issue-63479-match-fnptr.stderr

@@ -1,4 +1,4 @@
-warning: function pointers and unsized pointers in patterns do not behave deterministically. See https://github.com/rust-lang/rust/issues/70861 for details.
+warning: function pointers and unsized pointers in patterns behave unpredictably and should not be relied upon. See https://github.com/rust-lang/rust/issues/70861 for details.
   --> $DIR/issue-63479-match-fnptr.rs:35:7
    |
 LL |     B(TEST) => println!("matched"),