Deduplicate code for formatting RangeEnd

Author: estebank

src/librustc/hir/mod.rs

@@ -989,6 +989,15 @@ pub enum RangeEnd {
     Excluded,
 }
 
+impl fmt::Display for RangeEnd {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str(match self {
+            RangeEnd::Included => "..=",
+            RangeEnd::Excluded => "..",
+        })
+    }
+}
+
 #[derive(RustcEncodable, RustcDecodable, Debug, HashStable)]
 pub enum PatKind {
     /// Represents a wildcard pattern (i.e., `_`).

src/librustc_mir/hair/pattern/_match.rs

@@ -482,12 +482,9 @@ impl<'tcx> Constructor<'tcx> {
                 // Get the right sign on the output:
                 let ty = ty::ParamEnv::empty().and(*ty);
                 format!(
-                    "{}..{}{}",
+                    "{}{}{}",
                     ty::Const::from_bits(tcx, *lo, ty),
-                    match range_end {
-                        RangeEnd::Included => "=",
-                        RangeEnd::Excluded => "",
-                    },
+                    range_end,
                     ty::Const::from_bits(tcx, *hi, ty),
                 )
             }

src/librustc_mir/hair/pattern/mod.rs

@@ -312,10 +312,7 @@ impl<'tcx> fmt::Display for Pat<'tcx> {
             }
             PatKind::Range(PatRange { lo, hi, end }) => {
                 write!(f, "{}", lo)?;
-                match end {
-                    RangeEnd::Included => write!(f, "..=")?,
-                    RangeEnd::Excluded => write!(f, "..")?,
-                }
+                write!(f, "{}", end)?;
                 write!(f, "{}", hi)
             }
             PatKind::Slice { ref prefix, ref slice, ref suffix } |