diff --git a/include/tree_sitter/parser.h b/include/tree_sitter/parser.h
index 0e73bc67..e9a0dfff 100644
--- a/include/tree_sitter/parser.h
+++ b/include/tree_sitter/parser.h
@@ -47,10 +47,6 @@ static inline TSTree *ts_lexer_accept(TSLexer *lexer, TSSymbol symbol,
   return lexer->accept_fn(lexer, symbol, is_hidden);
 }
 
-static inline int ts_lexer_is_done(const TSLexer *lexer) {
-  return lexer->chunk_size == 0 && lexer->position_in_chunk > 0;
-}
-
 typedef unsigned short TSStateId;
 
 typedef enum {
@@ -111,11 +107,10 @@ struct TSLanguage {
 #define ADVANCE(state_index)                                  \
   {                                                           \
     DEBUG_LEX("ADVANCE %d", state_index);                     \
-    if (ts_lexer_is_done(lexer)) {                            \
+    if (!ts_lexer_advance(lexer)) {                           \
       DEBUG_LEX("END");                                       \
-      return ts_lexer_accept(lexer, ts_builtin_sym_error, 0); \
+      return ts_lexer_accept(lexer, ts_builtin_sym_end, 0); \
     }                                                         \
-    ts_lexer_advance(lexer);                                  \
     lex_state = state_index;                                  \
     goto next_state;                                          \
   }
diff --git a/spec/runtime/document_spec.cc b/spec/runtime/document_spec.cc
index 03a48bde..9c2af48e 100644
--- a/spec/runtime/document_spec.cc
+++ b/spec/runtime/document_spec.cc
@@ -76,41 +76,73 @@ describe("Document", [&]() {
       delete reader;
     });
 
-    describe("modifying the end of the input", [&]() {
-      before_each([&]() {
-        size_t position(string("{ \"key\": [1, 2]").length());
-        string inserted_text(", \"key2\": 4");
+    auto insert_text = [&](size_t position, string text) {
+      reader->content.insert(position, text);
+      ts_document_edit(doc, { position, 0, text.length() });
+    };
 
-        reader->content.insert(position, inserted_text);
-        ts_document_edit(doc, { position, 0, inserted_text.length() });
-      });
+    auto delete_text = [&](size_t position, size_t length) {
+      reader->content.erase(position, length);
+      ts_document_edit(doc, { position, length, 0 });
+    };
 
+    describe("inserting tokens near the end of the input", [&]() {
       it("updates the parse tree", [&]() {
+        insert_text(
+            string("{ \"key\": [1, 2]").length(),
+            ", \"key2\": 4");
+
         AssertThat(string(ts_node_string(ts_document_root_node(doc))), Equals(
             "(DOCUMENT (object (string) (array (number) (number)) (string) (number)))"));
       });
 
       it("re-reads only the changed portion of the input", [&]() {
+        insert_text(
+            string("{ \"key\": [1, 2]").length(),
+            ", \"key2\": 4");
+
         AssertThat(reader->strings_read.size(), Equals<size_t>(2));
         AssertThat(reader->strings_read[1], Equals(", \"key2\": 4 }"));
       });
     });
 
-    describe("modifying the beginning of the input", [&]() {
-      before_each([&]() {
-        size_t position(string("{ ").length());
-        string inserted_text("\"key2\": 4, ");
+    describe("inserting text into an existing token", [&]() {
+      it("updates the parse three", [&]() {
+        insert_text(
+            string("{ \"key").length(),
+            "12345");
 
-        reader->content.insert(position, inserted_text);
-        ts_document_edit(doc, { position, 0, inserted_text.length() });
+        AssertThat(string(ts_node_string(ts_document_root_node(doc))), Equals(
+            "(DOCUMENT (object (string) (array (number) (number))))"));
       });
+    });
 
+    describe("deleting an important part of a token", [&]() {
+      it("updates the parse tree, creating an error", [&]() {
+        delete_text(
+            string("{ \"key").length(),
+            1);
+
+        AssertThat(string(ts_node_string(ts_document_root_node(doc))), Equals(
+            "(DOCUMENT (end))"));
+      });
+    });
+
+    describe("inserting tokens near the beginning of the input", [&]() {
       it("updates the parse tree", [&]() {
+        insert_text(
+            string("{ ").length(),
+            "\"key2\": 4, ");
+
         AssertThat(string(ts_node_string(ts_document_root_node(doc))), Equals(
             "(DOCUMENT (object (string) (number) (string) (array (number) (number))))"));
       });
 
       it_skip("re-reads only the changed portion of the input", [&]() {
+        insert_text(
+            string("{ ").length(),
+            "\"key2\": 4, ");
+
         AssertThat(reader->strings_read.size(), Equals<size_t>(2));
         AssertThat(reader->strings_read[1], Equals("\"key2\": 4, "));
       });