check for unbalanced tick pairs in doc-markdown

Author: ebobrow

clippy_lints/src/doc.rs

@@ -485,6 +485,8 @@ fn check_doc<'a, Events: Iterator<Item = (pulldown_cmark::Event<'a>, Range<usize
     let mut in_heading = false;
     let mut is_rust = false;
     let mut edition = None;
+    let mut ticks_unbalanced = false;
+    let mut text_to_check = Vec::new();
     for (event, range) in events {
         match event {
             Start(CodeBlock(ref kind)) => {
@@ -516,34 +518,54 @@ fn check_doc<'a, Events: Iterator<Item = (pulldown_cmark::Event<'a>, Range<usize
             Html(_html) => (),             // HTML is weird, just ignore it
             SoftBreak | HardBreak | TaskListMarker(_) | Code(_) | Rule => (),
             FootnoteReference(text) | Text(text) => {
-                if Some(&text) == in_link.as_ref() {
+                if Some(&text) == in_link.as_ref() || ticks_unbalanced {
                     // Probably a link of the form `<http://example.com>`
                     // Which are represented as a link to "http://example.com" with
                     // text "http://example.com" by pulldown-cmark
                     continue;
                 }
-                headers.safety |= in_heading && text.trim() == "Safety";
-                headers.errors |= in_heading && text.trim() == "Errors";
-                headers.panics |= in_heading && text.trim() == "Panics";
-                let index = match spans.binary_search_by(|c| c.0.cmp(&range.start)) {
-                    Ok(o) => o,
-                    Err(e) => e - 1,
-                };
-                let (begin, span) = spans[index];
-                if in_code {
-                    if is_rust {
-                        let edition = edition.unwrap_or_else(|| cx.tcx.sess.edition());
-                        check_code(cx, &text, edition, span);
-                    }
+                if text.contains('`') && !in_code {
+                    let (_, start) = spans[0];
+                    let span = if let Some((_, end)) = spans.last() {
+                        start.with_hi(end.hi())
+                    } else {
+                        start
+                    };
+                    span_lint(
+                        cx,
+                        DOC_MARKDOWN,
+                        span,
+                        "backticks are unbalanced; one may be missing a pair",
+                    );
+                    ticks_unbalanced = true;
                 } else {
-                    // Adjust for the beginning of the current `Event`
-                    let span = span.with_lo(span.lo() + BytePos::from_usize(range.start - begin));
-
-                    check_text(cx, valid_idents, &text, span);
+                    headers.safety |= in_heading && text.trim() == "Safety";
+                    headers.errors |= in_heading && text.trim() == "Errors";
+                    headers.panics |= in_heading && text.trim() == "Panics";
+                    let index = match spans.binary_search_by(|c| c.0.cmp(&range.start)) {
+                        Ok(o) => o,
+                        Err(e) => e - 1,
+                    };
+                    let (begin, span) = spans[index];
+                    if in_code {
+                        if is_rust {
+                            let edition = edition.unwrap_or_else(|| cx.tcx.sess.edition());
+                            check_code(cx, &text, edition, span);
+                        }
+                    } else {
+                        // Adjust for the beginning of the current `Event`
+                        let span = span.with_lo(span.lo() + BytePos::from_usize(range.start - begin));
+                        text_to_check.push((text, span));
+                    }
                 }
             },
         }
     }
+    if !ticks_unbalanced {
+        for (text, span) in text_to_check {
+            check_text(cx, valid_idents, &text, span);
+        }
+    }
     headers
 }
 

clippy_lints/src/if_let_mutex.rs

@@ -83,7 +83,7 @@ impl<'tcx> LateLintPass<'tcx> for IfLetMutex {
     }
 }
 
-/// Checks if `Mutex::lock` is called in the `if let _ = expr.
+/// Checks if `Mutex::lock` is called in the `if let` expr.
 pub struct OppVisitor<'a, 'tcx> {
     mutex_lock_called: bool,
     found_mutex: Option<&'tcx Expr<'tcx>>,

tests/ui/doc.rs

@@ -203,6 +203,12 @@ fn issue_2343() {}
 /// __|_ _|__||_|
 fn pulldown_cmark_crash() {}
 
+/// This is a doc comment with `unbalanced_tick marks and several words that
+/// should be `encompassed_by` tick marks because they `contain_underscores`.
+/// Because of the initial `unbalanced_tick` pair, the error message is
+/// very `confusing_and_misleading`.
+fn issue_6753() {}
+
 // issue #7033 - const_evaluatable_checked ICE
 struct S<T, const N: usize>
 where [(); N.checked_next_power_of_two().unwrap()]: {

tests/ui/doc.stderr

@@ -186,5 +186,15 @@ error: you should put `mycrate::Collection` between ticks in the documentation
 LL | /// An iterator over mycrate::Collection's values.
    |                      ^^^^^^^^^^^^^^^^^^^
 
-error: aborting due to 31 previous errors
+error: backticks are unbalanced; one may be missing a pair
+  --> $DIR/doc.rs:206:4
+   |
+LL |   /// This is a doc comment with `unbalanced_tick marks and several words that
+   |  ____^
+LL | | /// should be `encompassed_by` tick marks because they `contain_underscores`.
+LL | | /// Because of the initial `unbalanced_tick` pair, the error message is
+LL | | /// very `confusing_and_misleading`.
+   | |____________________________________^
+
+error: aborting due to 32 previous errors