diff --git a/codespan-lsp/CHANGELOG.md b/codespan-lsp/CHANGELOG.md
index 45dd67d..a9177c8 100644
--- a/codespan-lsp/CHANGELOG.md
+++ b/codespan-lsp/CHANGELOG.md
@@ -11,8 +11,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 -   The error type in `codespan-lsp` is replaced with the error type in the `codespan-reporting` crate.
     The error type is now `codespan_reporting::file::Error`.
--   The `lsp-types` dependency was updated to use a version range: `>=0.70, <0.83`,
-    which includes the latest updates in `0.82.0`.
+-   The `lsp-types` dependency was updated to use the version range: `>=0.84, <0.85`.
+    Compatibility was broken as a result of the [clarified numeric types] that this crate depended on.
+-   The `character_to_line_offset` function was made private to reduce the chance of future public breakages.
+
+[clarified numeric types]: https://github.com/gluon-lang/lsp-types/pull/186
 
 ## [0.10.1] - 2020-08-17
 
diff --git a/codespan-lsp/Cargo.toml b/codespan-lsp/Cargo.toml
index b9c060b..775aaa6 100644
--- a/codespan-lsp/Cargo.toml
+++ b/codespan-lsp/Cargo.toml
@@ -16,5 +16,5 @@ codespan-reporting = { version = "0.9.5", path = "../codespan-reporting" }
 # will be valid for all the versions in this range. Getting this range wrong
 # could potentially break down-stream builds on a `cargo update`. This is an
 # absolute no-no, breaking much of what we enjoy about Cargo!
-lsp-types = ">=0.70, <0.83"
+lsp-types = ">=0.84, <0.85"
 url = "2"
diff --git a/codespan-lsp/src/lib.rs b/codespan-lsp/src/lib.rs
index 99b9a00..c4d659c 100644
--- a/codespan-lsp/src/lib.rs
+++ b/codespan-lsp/src/lib.rs
@@ -27,8 +27,8 @@ fn location_to_position(
         Err(Error::InvalidCharBoundary { given })
     } else {
         let line_utf16 = line_str[..column].encode_utf16();
-        let character = line_utf16.count() as u64;
-        let line = line as u64;
+        let character = line_utf16.count() as u32;
+        let line = line as u32;
 
         Ok(LspPosition { line, character })
     }
@@ -77,7 +77,7 @@ where
     })
 }
 
-pub fn character_to_line_offset(line: &str, character: u64) -> Result<usize, Error> {
+fn character_to_line_offset(line: &str, character: u32) -> Result<usize, Error> {
     let line_len = line.len();
     let mut character_offset = 0;
 
@@ -90,7 +90,7 @@ pub fn character_to_line_offset(line: &str, character: u64) -> Result<usize, Err
             return Ok(line_len - chars_off - ch_off);
         }
 
-        character_offset += ch.len_utf16() as u64;
+        character_offset += ch.len_utf16() as u32;
     }
 
     // Handle positions after the last character on the line