Auto merge of #30711 - nrc:json-errs, r=huonw

The compiler can emit errors and warning in JSON format. This is a more easily machine readable form then the usual error output.

Closes #10492, closes #14863.

1 files changed, 19 insertions, 14 deletions

diff --git a/src/libsyntax/errors/mod.rs b/src/libsyntax/errors/mod.rs
index a2fae975148..f269dee31d9 100644
--- a/src/libsyntax/errors/mod.rs
+++ b/src/libsyntax/errors/mod.rs
@@ -24,6 +24,7 @@ use std::rc::Rc;
 use term;
 
 pub mod emitter;
+pub mod json;
 
 #[derive(Clone)]
 pub enum RenderSpan {
@@ -275,12 +276,12 @@ pub struct Handler {
 }
 
 impl Handler {
-    pub fn new(color_config: ColorConfig,
-               registry: Option<diagnostics::registry::Registry>,
-               can_emit_warnings: bool,
-               treat_err_as_bug: bool,
-               cm: Rc<codemap::CodeMap>)
-               -> Handler {
+    pub fn with_tty_emitter(color_config: ColorConfig,
+                            registry: Option<diagnostics::registry::Registry>,
+                            can_emit_warnings: bool,
+                            treat_err_as_bug: bool,
+                            cm: Rc<codemap::CodeMap>)
+                            -> Handler {
         let emitter = Box::new(EmitterWriter::stderr(color_config, registry, cm));
         Handler::with_emitter(can_emit_warnings, treat_err_as_bug, emitter)
     }
@@ -547,14 +548,7 @@ impl fmt::Display for Level {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         use std::fmt::Display;
 
-        match *self {
-            Bug => "error: internal compiler error".fmt(f),
-            Fatal | Error => "error".fmt(f),
-            Warning => "warning".fmt(f),
-            Note => "note".fmt(f),
-            Help => "help".fmt(f),
-            Cancelled => unreachable!(),
-        }
+        self.to_str().fmt(f)
     }
 }
 
@@ -568,6 +562,17 @@ impl Level {
             Cancelled => unreachable!(),
         }
     }
+
+    fn to_str(self) -> &'static str {
+        match self {
+            Bug => "error: internal compiler error",
+            Fatal | Error => "error",
+            Warning => "warning",
+            Note => "note",
+            Help => "help",
+            Cancelled => panic!("Shouldn't call on cancelled error"),
+        }
+    }
 }
 
 pub fn expect<T, M>(diag: &Handler, opt: Option<T>, msg: M) -> T where