..

src/ast/optimization.rs

@@ -21,6 +21,10 @@ pub fn optimize_expr(expr: TypedExpr) -> TypedExpr {
 }
 
 pub fn bubble_binop_vars(expr: TypedExpr) -> TypedExpr {
+    if expr.is_const() {
+        return expr;
+    }
+
     let expr = reorder_commutative_expr(expr);
 
     let expr = match expr {
@@ -138,6 +142,10 @@ fn optimize_special_cases(lhs: TypedExpr, op: BinOp, rhs: TypedExpr) -> TypedExp
             lhs
         },
 
+        // Subtraction by zero
+        (lhs, TypedExpr::Int { value: 0, .. }) if matches!(op, BinOp::Sub) => lhs,
+        (lhs, TypedExpr::Float { value: 0.0, .. }) if matches!(op, BinOp::Sub) => lhs,
+
         // Multiplication/Division by one
         (lhs, TypedExpr::Int { value: 1, .. }) if matches!(op, BinOp::Mul | BinOp::Div) => lhs,
         (lhs, TypedExpr::Float { value: 1.0, .. }) if matches!(op, BinOp::Mul | BinOp::Div) => lhs,

src/ast/typed.rs

@@ -78,8 +78,11 @@ impl fmt::Display for Type {
 
 impl TypedExpr {
     pub fn cast_to_float(self) -> TypedExpr {
-        Self::IntToFloat {
+        match self {
+            Self::IntToFloat { .. } | Self::Float { .. } => self,
+            _ => Self::IntToFloat {
                 value: Box::new(self),
+            },
         }
     }