syntax: Only use color output if the terminal supports it

Author: erickt

src/libsyntax/errors/emitter.rs

@@ -683,8 +683,14 @@ enum Destination {
 impl Destination {
     fn from_stderr() -> Destination {
         match term::stderr() {
-            Some(t) => Terminal(t),
-            None    => Raw(Box::new(io::stderr())),
+            Some(t) => {
+                if t.supports_color() {
+                    Terminal(t)
+                } else {
+                    Raw(Box::new(io::stderr()))
+                }
+            }
+            None => Raw(Box::new(io::stderr())),
         }
     }
 

src/libterm/terminfo/mod.rs

@@ -230,7 +230,9 @@ impl<T: Write + Send> Terminal for TerminfoTerminal<T> {
                          ("sgr", &[Param::Number(0)]),
                          ("op", &[])]
                             .iter()
-                            .filter_map(|&(cap, params)| self.ti.strings.get(cap).map(|c| (c, params)))
+                            .filter_map(|&(cap, params)| {
+                                self.ti.strings.get(cap).map(|c| (c, params))
+                            })
                             .next() {
             Some((op, params)) => {
                 match expand(op, params, &mut Variables::new()) {