rustdoc: improve <wbr>-insertion for SCREAMING_CAMEL_CASE

Author: notriddle

src/librustdoc/html/escape.rs

@@ -108,7 +108,7 @@ impl<'a> fmt::Display for EscapeBodyTextWithWbr<'a> {
                 || pk.map_or(true, |(_, t)| t.chars().any(|c| c.is_uppercase()));
             let next_is_underscore = || pk.map_or(true, |(_, t)| t.contains('_'));
             let next_is_colon = || pk.map_or(true, |(_, t)| t.contains(':'));
-            if i - last > 3 && is_uppercase() && !next_is_uppercase() {
+            if i - last > 3 && is_uppercase() && !next_is_uppercase() && !next_is_underscore() {
                 EscapeBodyText(&text[last..i]).fmt(fmt)?;
                 fmt.write_str("<wbr>")?;
                 last = i;

src/librustdoc/html/escape/tests.rs

@@ -24,6 +24,10 @@ fn escape_body_text_with_wbr() {
     assert_eq!(&E("first:second").to_string(), "first:<wbr>second");
     assert_eq!(&E("first::second").to_string(), "first::<wbr>second");
     assert_eq!(&E("MY_CONSTANT").to_string(), "MY_<wbr>CONSTANT");
+    assert_eq!(
+        &E("_SIDD_MASKED_NEGATIVE_POLARITY").to_string(),
+        "_SIDD_<wbr>MASKED_<wbr>NEGATIVE_<wbr>POLARITY"
+    );
     // a string won't get wrapped if it's less than 8 bytes
     assert_eq!(&E("HashSet").to_string(), "HashSet");
     // an individual word won't get wrapped if it's less than 4 bytes