fix: enable serde default for span in symbolic expressions

Author: hugocaillard

clarity/src/vm/representations.rs

@@ -454,13 +454,17 @@ pub struct SymbolicExpression {
     pub id: u64,
 
     #[cfg(feature = "developer-mode")]
+    #[serde(default)]
     pub span: Span,
 
     #[cfg(feature = "developer-mode")]
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
     pub pre_comments: Vec<(String, Span)>,
     #[cfg(feature = "developer-mode")]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub end_line_comment: Option<String>,
     #[cfg(feature = "developer-mode")]
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
     pub post_comments: Vec<(String, Span)>,
 }
 
@@ -650,7 +654,7 @@ impl fmt::Display for SymbolicExpression {
     }
 }
 
-#[derive(Debug, Serialize, Deserialize, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+#[derive(Debug, Serialize, Deserialize, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Default)]
 pub struct Span {
     pub start_line: u32,
     pub start_column: u32,
@@ -666,12 +670,7 @@ impl Span {
         end_column: 0,
     };
 
-    pub fn zero() -> Span {
-        Span {
-            start_line: 0,
-            start_column: 0,
-            end_line: 0,
-            end_column: 0,
-        }
+    pub fn zero() -> Self {
+        Self::default()
     }
 }