Buffer errors in MIR borrow check

(pnkfelix updated to address tidy, and to change the buffer from
`Vec<DiagnosticBuilder<'errs>>` to a `Vec<Diagnostic>` in order to
avoid painful lifetime maintenance.)

1 files changed, 12 insertions, 0 deletions

diff --git a/src/librustc_errors/diagnostic_builder.rs b/src/librustc_errors/diagnostic_builder.rs
index 24ece514a47..8f99ad87cb8 100644
--- a/src/librustc_errors/diagnostic_builder.rs
+++ b/src/librustc_errors/diagnostic_builder.rs
@@ -88,6 +88,18 @@ impl<'a> DiagnosticBuilder<'a> {
         self.cancel();
     }
 
+    /// Buffers the diagnostic for later emission.
+    pub fn buffer(self, buffered_diagnostics: &mut Vec<Diagnostic>) {
+        // We need to use `ptr::read` because `DiagnosticBuilder`
+        // implements `Drop`.
+        let diagnostic;
+        unsafe {
+            diagnostic = ::std::ptr::read(&self.diagnostic);
+            ::std::mem::forget(self);
+        };
+        buffered_diagnostics.push(diagnostic);
+    }
+
     pub fn is_error(&self) -> bool {
         match self.level {
             Level::Bug |