Update grader

src/ir/mod.rs

@@ -527,7 +527,12 @@ impl TryFrom<&ast::Constant> for Constant {
                     ast::IntegerBase::Octal => Self::OCTAL,
                     ast::IntegerBase::Hexadecimal => Self::HEXADECIMAL,
                 };
-                let value = u128::from_str_radix(integer.number.deref(), pat).unwrap();
+
+                let value = if integer.suffix.unsigned {
+                    u128::from_str_radix(integer.number.deref(), pat).unwrap()
+                } else {
+                    i128::from_str_radix(integer.number.deref(), pat).unwrap() as u128
+                };
 
                 let is_signed = !integer.suffix.unsigned && {
                     // Even if `suffix` represents `signed`, integer literal cannot be translated

src/ir/parse.rs

@@ -580,6 +580,14 @@ peg::parser! {
                     suffix,
                 }
             }
+        /
+            "0" suffix:ast_integer_suffix() {
+                ast::Integer {
+                    base: ast::IntegerBase::Decimal,
+                    number: Box::from("0"),
+                    suffix,
+                }
+            }
         /
             "<ast_integer>" {
                 todo!()