rollup merge of #21289: brson/errorcodes

This does the bare minimum to make registration of error codes work again. After this patch, every call to `span_err!` with an error code gets that error code validated against a list in that crate and a new tidy script `errorck.py` validates that no error codes are duplicated globally.

There are further improvements to be made yet, detailed in #19624.

r? @nikomatsakis

3 files changed, 25 insertions, 0 deletions

diff --git a/src/libsyntax/diagnostic.rs b/src/libsyntax/diagnostic.rs
index 7213b0fa955..b26ec64c24b 100644
--- a/src/libsyntax/diagnostic.rs
+++ b/src/libsyntax/diagnostic.rs
@@ -92,6 +92,10 @@ impl SpanHandler {
         self.handler.emit(Some((&self.cm, sp)), msg, Fatal);
         panic!(FatalError);
     }
+    pub fn span_fatal_with_code(&self, sp: Span, msg: &str, code: &str) -> ! {
+        self.handler.emit_with_code(Some((&self.cm, sp)), msg, code, Fatal);
+        panic!(FatalError);
+    }
     pub fn span_err(&self, sp: Span, msg: &str) {
         self.handler.emit(Some((&self.cm, sp)), msg, Error);
         self.handler.bump_err_count();
diff --git a/src/libsyntax/diagnostics/macros.rs b/src/libsyntax/diagnostics/macros.rs
index 34a193dffd3..9321d3ca3df 100644
--- a/src/libsyntax/diagnostics/macros.rs
+++ b/src/libsyntax/diagnostics/macros.rs
@@ -15,6 +15,14 @@ macro_rules! register_diagnostic {
 }
 
 #[macro_export]
+macro_rules! span_fatal {
+    ($session:expr, $span:expr, $code:ident, $($message:tt)*) => ({
+        __diagnostic_used!($code);
+        $session.span_fatal_with_code($span, format!($($message)*).as_slice(), stringify!($code))
+    })
+}
+
+#[macro_export]
 macro_rules! span_err {
     ($session:expr, $span:expr, $code:ident, $($message:tt)*) => ({
         __diagnostic_used!($code);
@@ -51,3 +59,9 @@ macro_rules! register_diagnostics {
     )
 }
 
+#[macro_export]
+macro_rules! register_long_diagnostics {
+    ($($code:tt: $description:tt),*) => (
+        $(register_diagnostic! { $code, $description })*
+    )
+}
diff --git a/src/libsyntax/diagnostics/plugin.rs b/src/libsyntax/diagnostics/plugin.rs
index 1469c50061c..0e99829fa1c 100644
--- a/src/libsyntax/diagnostics/plugin.rs
+++ b/src/libsyntax/diagnostics/plugin.rs
@@ -65,6 +65,13 @@ pub fn expand_diagnostic_used<'cx>(ecx: &'cx mut ExtCtxt,
         }
         ()
     });
+    with_registered_diagnostics(|diagnostics| {
+        if !diagnostics.contains_key(&code.name) {
+            ecx.span_err(span, &format!(
+                "used diagnostic code {} not registered", token::get_ident(code).get()
+            )[]);
+        }
+    });
     MacExpr::new(quote_expr!(ecx, ()))
 }