review comments

Author: estebank

src/librustc_errors/emitter.rs

@@ -1477,7 +1477,11 @@ impl EmitterWriter {
             Some(ref sm) => sm,
             None => return Ok(()),
         };
-        if !suggestion.has_valid_spans(&**sm) {
+
+        // Render the replacements for each suggestion
+        let suggestions = suggestion.splice_lines(&**sm);
+
+        if suggestions.is_empty() {
             // Suggestions coming from macros can have malformed spans. This is a heavy handed
             // approach to avoid ICEs by ignoring the suggestion outright.
             return Ok(());
@@ -1499,9 +1503,6 @@ impl EmitterWriter {
             Some(Style::HeaderMsg),
         );
 
-        // Render the replacements for each suggestion
-        let suggestions = suggestion.splice_lines(&**sm);
-
         let mut row_num = 2;
         let mut notice_capitalization = false;
         for (complete, parts, only_capitalization) in suggestions.iter().take(MAX_SUGGESTIONS) {

src/librustc_errors/lib.rs

@@ -144,18 +144,6 @@ pub struct SubstitutionPart {
 }
 
 impl CodeSuggestion {
-    /// Suggestions coming from macros can have malformed spans. This is a heavy handed approach
-    /// to avoid ICEs by ignoring the suggestion outright.
-    pub fn has_valid_spans(&self, cm: &SourceMap) -> bool {
-        !self.substitutions.iter().any(|subst| {
-            let invalid = subst.parts.iter().any(|item| cm.is_valid_span(item.span).is_err());
-            if invalid {
-                debug!("malformed span in suggestion: {:?}", subst);
-            }
-            invalid
-        })
-    }
-
     /// Returns the assembled code suggestions, whether they should be shown with an underline
     /// and whether the substitution only differs in capitalization.
     pub fn splice_lines(&self, cm: &SourceMap) -> Vec<(String, Vec<SubstitutionPart>, bool)> {
@@ -187,6 +175,15 @@ impl CodeSuggestion {
 
         self.substitutions
             .iter()
+            .filter(|subst| {
+                // Suggestions coming from macros can have malformed spans. This is a heavy
+                // handed approach to avoid ICEs by ignoring the suggestion outright.
+                let invalid = subst.parts.iter().any(|item| cm.is_valid_span(item.span).is_err());
+                if invalid {
+                    debug!("splice_lines: suggestion contains an invalid span: {:?}", subst);
+                }
+                !invalid
+            })
             .cloned()
             .map(|mut substitution| {
                 // Assumption: all spans are in the same file, and all spans