1 files changed, 22 insertions, 10 deletions
diff --git a/cli/lsp/tsc.rs b/cli/lsp/tsc.rs
index b5ce48fab..4a61d7403 100644
--- a/cli/lsp/tsc.rs
+++ b/cli/lsp/tsc.rs
@@ -38,6 +38,8 @@ use deno_core::OpFn;
 use deno_core::RuntimeOptions;
 use deno_runtime::tokio_util::create_basic_runtime;
 use log::warn;
+use lspower::jsonrpc::Error as LspError;
+use lspower::jsonrpc::Result as LspResult;
 use lspower::lsp;
 use regex::Captures;
 use regex::Regex;
@@ -1122,7 +1124,7 @@ impl Classifications {
   pub fn to_semantic_tokens(
     &self,
     line_index: Arc<LineIndex>,
-  ) -> lsp::SemanticTokens {
+  ) -> LspResult<lsp::SemanticTokens> {
     let token_count = self.spans.len() / 3;
     let mut builder = SemanticTokensBuilder::new();
     for i in 0..token_count {
@@ -1141,16 +1143,26 @@ impl Classifications {
       let start_pos = line_index.position_tsc(offset.into());
       let end_pos = line_index.position_tsc(TextSize::from(offset + length));
 
-      // start_pos.line == end_pos.line is always true as there are no multiline tokens
-      builder.push(
-        start_pos.line,
-        start_pos.character,
-        end_pos.character - start_pos.character,
-        token_type,
-        token_modifiers,
-      );
+      if start_pos.line == end_pos.line
+        && start_pos.character <= end_pos.character
+      {
+        builder.push(
+          start_pos.line,
+          start_pos.character,
+          end_pos.character - start_pos.character,
+          token_type,
+          token_modifiers,
+        );
+      } else {
+        log::error!(
+          "unexpected positions\nstart_pos: {:?}\nend_pos: {:?}",
+          start_pos,
+          end_pos
+        );
+        return Err(LspError::internal_error());
+      }
     }
-    builder.build(None)
+    Ok(builder.build(None))
   }
 
   fn get_token_type_from_classification(ts_classification: u32) -> u32 {