From 7effe633b0a729b641c7b8f1f8a21b97f9154b14 Mon Sep 17 00:00:00 2001
From: Mazdak Farrokhzad <twingoow@gmail.com>
Date: Tue, 8 Oct 2019 10:59:05 +0200
Subject: [PATCH] simplify integer_lit

---
 src/libsyntax/lib.rs           |  1 +
 src/libsyntax/parse/literal.rs | 15 ++++++---------
 2 files changed, 7 insertions(+), 9 deletions(-)

diff --git a/src/libsyntax/lib.rs b/src/libsyntax/lib.rs
index 03b00188e255e..09a47795a822a 100644
--- a/src/libsyntax/lib.rs
+++ b/src/libsyntax/lib.rs
@@ -17,6 +17,7 @@
 #![feature(proc_macro_internals)]
 #![feature(proc_macro_span)]
 #![feature(try_trait)]
+#![feature(slice_patterns)]
 #![feature(unicode_internals)]
 
 #![recursion_limit="256"]
diff --git a/src/libsyntax/parse/literal.rs b/src/libsyntax/parse/literal.rs
index fcd5b2782fd61..56a79bfe5d51c 100644
--- a/src/libsyntax/parse/literal.rs
+++ b/src/libsyntax/parse/literal.rs
@@ -426,15 +426,12 @@ fn integer_lit(symbol: Symbol, suffix: Option<Symbol>) -> Result<LitKind, LitErr
     let symbol = strip_underscores(symbol);
     let s = symbol.as_str();
 
-    let mut base = 10;
-    if s.len() > 1 && s.as_bytes()[0] == b'0' {
-        match s.as_bytes()[1] {
-            b'x' => base = 16,
-            b'o' => base = 8,
-            b'b' => base = 2,
-            _ => {}
-        }
-    }
+    let base = match s.as_bytes() {
+        [b'0', b'x', ..] => 16,
+        [b'0', b'o', ..] => 8,
+        [b'0', b'b', ..] => 2,
+        _ => 10,
+    };
 
     let ty = match suffix {
         Some(suf) => match suf {