diff --git a/shard.yml b/shard.yml
index 05dd360..741cfb5 100644
--- a/shard.yml
+++ b/shard.yml
@@ -8,7 +8,7 @@ targets:
   hence:
     main: src/cli/hence.cr
 
-crystal: 1.4.1
+crystal: 1.5.0
 
 license: MIT
 
diff --git a/src/hence/parser.cr b/src/hence/parser.cr
index 3c0147a..ac973d3 100644
--- a/src/hence/parser.cr
+++ b/src/hence/parser.cr
@@ -180,12 +180,12 @@ module Hence
         def initialize(@number : UInt16)
         end
 
-        def resolve(_data : Assembler::Data) : Bytes
+        def resolve(data : Assembler::Data) : Bytes
           n = Utils.split_u16(@number)
           Bytes[n[0], n[1]]
         end
 
-        def resolve_as_number(_data : Assembler::Data) : UInt16
+        def resolve_as_number(data : Assembler::Data) : UInt16
           @number
         end
 
@@ -219,11 +219,11 @@ module Hence
         def initialize(@bytes : Bytes)
         end
 
-        def resolve(_data : Assembler::Data) : Bytes
+        def resolve(data : Assembler::Data) : Bytes
           @bytes
         end
 
-        def resolve_as_number(_data : Assembler::Data) : UInt16
+        def resolve_as_number(data : Assembler::Data) : UInt16
           if @bytes.size == 1
             @bytes[0].to_u16
           else
@@ -242,7 +242,7 @@ module Hence
         def initialize(@string : String)
         end
 
-        def resolve(_data : Assembler::Data) : Bytes
+        def resolve(data : Assembler::Data) : Bytes
           if @string.bytesize == 1
             Bytes[0_u8, @string.bytes[0]]
           else
@@ -250,8 +250,8 @@ module Hence
           end
         end
 
-        def resolve_as_number(_data : Assembler::Data) : UInt16
-          slice = resolve(_data)
+        def resolve_as_number(data : Assembler::Data) : UInt16
+          slice = resolve(data)
 
           Utils.merge_u8(slice[0], slice[1])
         end