Move extra help to a span_label

Author: saethlin

src/diagnostics.rs

@@ -134,7 +134,7 @@ pub fn report_error<'tcx, 'mir>(
 ) -> Option<i64> {
     use InterpError::*;
 
-    let (title, helps) = match &e.kind() {
+    let (title, labels, helps) = match &e.kind() {
         MachineStop(info) => {
             let info = info.downcast_ref::<TerminationInfo>().expect("invalid MachineStop payload");
             use TerminationInfo::*;
@@ -146,6 +146,7 @@ pub fn report_error<'tcx, 'mir>(
                 Deadlock => Some("deadlock"),
                 MultipleSymbolDefinitions { .. } | SymbolShimClashing { .. } => None,
             };
+            let mut labels = vec![];
             #[rustfmt::skip]
             let helps = match info {
                 UnsupportedInIsolation(_) =>
@@ -154,17 +155,13 @@ pub fn report_error<'tcx, 'mir>(
                         (None, format!("or pass `-Zmiri-isolation-error=warn to configure Miri to return an error code from isolated operations (if supported for that operation) and continue with a warning")),
                     ],
                 ExperimentalUb { url, help, .. } => {
-                    let mut helps = Vec::new();
                     if let Some(help) = help {
-                        helps.push((Some(ecx.cur_span().data()), help.clone()));
+                        labels.push(help.clone());
                     }
-                    helps.push(
-                        (None, format!("this indicates a potential bug in the program: it performed an invalid operation, but the rules it violated are still experimental"))
-                    );
-                    helps.push(
+                    vec![
+                        (None, format!("this indicates a potential bug in the program: it performed an invalid operation, but the rules it violated are still experimental")),
                         (None, format!("see {} for further information", url))
-                    );
-                    helps
+                    ]
                 }
                 MultipleSymbolDefinitions { first, first_crate, second, second_crate, .. } =>
                     vec![
@@ -175,7 +172,7 @@ pub fn report_error<'tcx, 'mir>(
                     vec![(Some(*span), format!("the `{}` symbol is defined here", link_name))],
                 _ => vec![],
             };
-            (title, helps)
+            (title, labels, helps)
         }
         _ => {
             #[rustfmt::skip]
@@ -213,7 +210,7 @@ pub fn report_error<'tcx, 'mir>(
                     ],
                 _ => vec![],
             };
-            (Some(title), helps)
+            (Some(title), vec![], helps)
         }
     };
 
@@ -226,6 +223,7 @@ pub fn report_error<'tcx, 'mir>(
         DiagLevel::Error,
         &if let Some(title) = title { format!("{}: {}", title, msg) } else { msg.clone() },
         msg,
+        labels,
         helps,
         &stacktrace,
     );
@@ -270,6 +268,7 @@ fn report_msg<'tcx>(
     diag_level: DiagLevel,
     title: &str,
     span_msg: String,
+    labels: Vec<String>,
     mut helps: Vec<(Option<SpanData>, String)>,
     stacktrace: &[FrameInfo<'tcx>],
 ) {
@@ -288,6 +287,12 @@ fn report_msg<'tcx>(
         err.note(&span_msg);
         err.note("(no span available)");
     }
+
+    // Add extra labels to the primary span.
+    for label in labels {
+        err.span_label(span, label);
+    }
+
     // Show help messages.
     if !helps.is_empty() {
         // Add visual separator before backtrace.
@@ -422,7 +427,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
                     _ => ("tracking was triggered", DiagLevel::Note),
                 };
 
-                report_msg(*this.tcx, diag_level, title, msg, vec![], &stacktrace);
+                report_msg(*this.tcx, diag_level, title, msg, vec![], vec![], &stacktrace);
             }
         });
     }