From 257bff3192e2c7313a4f8cfcac8839a573b42f6b Mon Sep 17 00:00:00 2001
From: Ulrik Sverdrup <bluss@users.noreply.github.com>
Date: Fri, 22 Jan 2016 18:19:00 +0100
Subject: [PATCH] Move cold panic functions in Option and Result

Move functions out of their impl blocks; avoids unnecessary
monomorphization by type parameters that are irrelevant to the message
output.
---
 src/libcore/option.rs | 16 +++++++++-------
 src/libcore/result.rs | 30 +++++++++---------------------
 2 files changed, 18 insertions(+), 28 deletions(-)

diff --git a/src/libcore/option.rs b/src/libcore/option.rs
index 7174661d281..eeb0c173b9b 100644
--- a/src/libcore/option.rs
+++ b/src/libcore/option.rs
@@ -295,16 +295,10 @@ impl<T> Option<T> {
     pub fn expect(self, msg: &str) -> T {
         match self {
             Some(val) => val,
-            None => Self::expect_failed(msg),
+            None => expect_failed(msg),
         }
     }
 
-    #[inline(never)]
-    #[cold]
-    fn expect_failed(msg: &str) -> ! {
-        panic!("{}", msg)
-    }
-
     /// Moves the value `v` out of the `Option<T>` if it is `Some(v)`.
     ///
     /// # Panics
@@ -703,6 +697,14 @@ impl<T: Default> Option<T> {
     }
 }
 
+// This is a separate function to reduce the code size of .expect() itself.
+#[inline(never)]
+#[cold]
+fn expect_failed(msg: &str) -> ! {
+    panic!("{}", msg)
+}
+
+
 /////////////////////////////////////////////////////////////////////////////
 // Trait implementations
 /////////////////////////////////////////////////////////////////////////////
diff --git a/src/libcore/result.rs b/src/libcore/result.rs
index b91cc1b3e6a..9bd6ed12798 100644
--- a/src/libcore/result.rs
+++ b/src/libcore/result.rs
@@ -684,16 +684,10 @@ impl<T, E: fmt::Debug> Result<T, E> {
     pub fn unwrap(self) -> T {
         match self {
             Ok(t) => t,
-            Err(e) => Self::unwrap_failed(e),
+            Err(e) => unwrap_failed("called `Result::unwrap()` on an `Err` value", e),
         }
     }
 
-    #[inline(never)]
-    #[cold]
-    fn unwrap_failed(error: E) -> ! {
-        panic!("called `Result::unwrap()` on an `Err` value: {:?}", error)
-    }
-
     /// Unwraps a result, yielding the content of an `Ok`.
     ///
     /// # Panics
@@ -711,15 +705,9 @@ impl<T, E: fmt::Debug> Result<T, E> {
     pub fn expect(self, msg: &str) -> T {
         match self {
             Ok(t) => t,
-            Err(e) => Self::expect_failed(msg, e),
+            Err(e) => unwrap_failed(msg, e),
         }
     }
-
-    #[inline(never)]
-    #[cold]
-    fn expect_failed(msg: &str, error: E) -> ! {
-        panic!("{}: {:?}", msg, error)
-    }
 }
 
 impl<T: fmt::Debug, E> Result<T, E> {
@@ -745,17 +733,17 @@ impl<T: fmt::Debug, E> Result<T, E> {
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn unwrap_err(self) -> E {
         match self {
-            Ok(t) => Self::unwrap_err_failed(t),
+            Ok(t) => unwrap_failed("called `Result::unwrap_err()` on an `Ok` value", t),
             Err(e) => e,
         }
     }
+}
 
-    #[inline(never)]
-    #[cold]
-    fn unwrap_err_failed(t: T) -> ! {
-        panic!("called `Result::unwrap_err()` on an `Ok` value: {:?}", t)
-    }
-
+// This is a separate function to reduce the code size of the methods
+#[inline(never)]
+#[cold]
+fn unwrap_failed<E: fmt::Debug>(msg: &str, error: E) -> ! {
+    panic!("{}: {:?}", msg, error)
 }
 
 /////////////////////////////////////////////////////////////////////////////