diff --git a/src/librustdoc/html/escape.rs b/src/librustdoc/html/escape.rs
index 691f86847b56d..31a2701f06a54 100644
--- a/src/librustdoc/html/escape.rs
+++ b/src/librustdoc/html/escape.rs
@@ -108,7 +108,17 @@ 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() {
+            // Check for CamelCase.
+            //
+            // `i - last > 3` avoids turning FmRadio into Fm<wbr>Radio, which is technically
+            // correct, but needlessly bloated.
+            //
+            // is_uppercase && !next_is_uppercase checks for camelCase. HTTPSProxy,
+            // for example, should become HTTPS<wbr>Proxy.
+            //
+            // !next_is_underscore avoids turning TEST_RUN into TEST<wbr>_<wbr>RUN, which is also
+            // needlessly bloated.
+            if i - last > 3 && is_uppercase() && !next_is_uppercase() && !next_is_underscore() {
                 EscapeBodyText(&text[last..i]).fmt(fmt)?;
                 fmt.write_str("<wbr>")?;
                 last = i;
diff --git a/src/librustdoc/html/escape/tests.rs b/src/librustdoc/html/escape/tests.rs
index a09649e9e18dc..de702e1606353 100644
--- a/src/librustdoc/html/escape/tests.rs
+++ b/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