diff --git a/src/lexstate.c b/src/lexstate.c
index 79f275717..eb4b4939c 100644
--- a/src/lexstate.c
+++ b/src/lexstate.c
@@ -120,7 +120,7 @@ unsigned int rbs_peek(rbs_lexer_t *lexer) {
 }
 
 bool rbs_next_char(rbs_lexer_t *lexer, unsigned int *codepoint, size_t *byte_len) {
-    if (RBS_UNLIKELY(lexer->current.byte_pos == lexer->end_pos)) {
+    if (RBS_UNLIKELY(lexer->current.byte_pos >= lexer->end_pos)) {
         return false;
     }
 
diff --git a/test/rbs/type_parsing_test.rb b/test/rbs/type_parsing_test.rb
index 9a95f146e..f58c42c68 100644
--- a/test/rbs/type_parsing_test.rb
+++ b/test/rbs/type_parsing_test.rb
@@ -1074,4 +1074,23 @@ def test_parse__byte_range_incorrect_in_euc_jp
     assert_equal RBS::TypeName.parse("Foo"),
                  Parser.parse_type(euc, byte_range: 2...).name
   end
+
+  def test_parse__byte_range_ending_mid_character
+    source = '"日本語" | Integer'
+
+    # Character count 5 as a byte offset lands inside `本` (bytes 4...7). The
+    # lexer used to step over the boundary and read the whole string instead.
+    assert_raises RBS::ParsingError do
+      Parser.parse_type(source, byte_range: 0...'"日本語"'.size)
+    end
+
+    Parser.parse_type(source, byte_range: 0...'"日本語"'.bytesize, require_eof: true).tap do |type|
+      assert_instance_of Types::Literal, type
+      assert_equal "日本語", type.literal
+    end
+
+    Parser.parse_type("Integer", byte_range: 0...9999).tap do |type|
+      assert_instance_of Types::ClassInstance, type
+    end
+  end
 end