Fix location parsing for Block

Signed-off-by: Alexandre Terrasa <alexandre.terrasa@shopify.com>

Author: Morriar

src/parser.c

@@ -722,11 +722,17 @@ static bool parse_function(rbs_parser_t *parser, bool accept_type_binding, parse
   }
 
   bool required = true;
+  rbs_range_t block_range;
+
   if (parser->next_token.type == pQUESTION && parser->next_token2.type == pLBRACE) {
     // Optional block
+    block_range.start = parser->next_token.range.start;
     required = false;
     rbs_parser_advance(parser);
+  } else if (parser->next_token.type == pLBRACE) {
+    block_range.start = parser->next_token.range.start;
   }
+
   if (parser->next_token.type == pLBRACE) {
     rbs_parser_advance(parser);
 
@@ -746,9 +752,12 @@ static bool parse_function(rbs_parser_t *parser, bool accept_type_binding, parse
     rbs_node_t *block_return_type = NULL;
     CHECK_PARSE(parse_optional(parser, &block_return_type));
 
+    ADVANCE_ASSERT(parser, pRBRACE);
+
+    block_range.end = parser->current_token.range.end;
+    rbs_location_t *loc = rbs_location_new(ALLOCATOR(), block_range);
+
     rbs_node_t *block_function = NULL;
-    function_range.end = parser->current_token.range.end;
-    rbs_location_t *loc = rbs_location_new(ALLOCATOR(), function_range);
     if (rbs_is_untyped_params(&block_params)) {
       block_function = (rbs_node_t *) rbs_types_untyped_function_new(ALLOCATOR(), loc, block_return_type);
     } else {
@@ -767,8 +776,6 @@ static bool parse_function(rbs_parser_t *parser, bool accept_type_binding, parse
     }
 
     block = rbs_types_block_new(ALLOCATOR(), loc, block_function, required, self_type);
-
-    ADVANCE_ASSERT(parser, pRBRACE);
   }
 
   ADVANCE_ASSERT(parser, pARROW);