Replace better_divergence_checking feature flag with exhaustive_patterns

Author: varkor

src/libcore/num/mod.rs

@@ -4210,6 +4210,7 @@ impl fmt::Display for TryFromIntError {
 
 #[unstable(feature = "try_from", issue = "33417")]
 impl From<!> for TryFromIntError {
+    #[allow(unreachable_code)]
     fn from(never: !) -> TryFromIntError {
         never
     }

src/librustc_mir/hair/pattern/check_match.rs

@@ -227,7 +227,7 @@ impl<'a, 'tcx> MatchVisitor<'a, 'tcx> {
                 let scrutinee_is_uninhabited = if self.tcx.features().exhaustive_patterns {
                     self.tcx.is_ty_uninhabited_from(module, pat_ty)
                 } else {
-                    if self.tcx.features().better_divergence_checking {
+                    if self.tcx.features().exhaustive_patterns {
                         pat_ty.conservative_is_uninhabited()
                     } else {
                         match pat_ty.sty {

src/librustc_typeck/check/mod.rs

@@ -1060,7 +1060,7 @@ fn check_fn<'a, 'gcx, 'tcx>(inherited: &'a Inherited<'a, 'gcx, 'tcx>,
         // If any of a function's parameters have a type that is uninhabited, then it
         // may never be called (because its arguments cannot be constructed). Therefore,
         // it must always diverge.
-        if fcx.tcx.features().better_divergence_checking {
+        if fcx.tcx.features().exhaustive_patterns {
             if arg_ty.conservative_is_uninhabited() {
                 fcx.diverges.set(fcx.diverges.get() | Diverges::Always);
             }
@@ -3673,7 +3673,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
 
         // Any expression that produces a value of an uninhabited type must have diverged.
         if ty.conservative_is_uninhabited() {
-            if ty.is_never() || self.tcx.features().better_divergence_checking {
+            if ty.is_never() || self.tcx.features().exhaustive_patterns {
                 self.diverges.set(self.diverges.get() | Diverges::Always);
             }
         }

src/libstd/error.rs

@@ -309,6 +309,7 @@ impl Error for string::FromUtf16Error {
 
 #[stable(feature = "str_parse_error2", since = "1.8.0")]
 impl Error for string::ParseError {
+    #[allow(unreachable_code)]
     fn description(&self) -> &str {
         match *self {}
     }

src/libstd/process.rs

@@ -1477,6 +1477,7 @@ impl<E: fmt::Debug> Termination for Result<(), E> {
 
 #[unstable(feature = "termination_trait_lib", issue = "43301")]
 impl Termination for ! {
+    #[allow(unreachable_code)]
     fn report(self) -> i32 { self }
 }
 

src/test/compile-fail/uninhabited-matches-better-divergence-checking.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(better_divergence_checking)]
+#![feature(exhaustive_patterns)]
 #![deny(unreachable_code)]
 
 pub enum Void {}