fix: add opSize back in to stack

src/main/wacc/backend/Stack.scala

@@ -23,7 +23,7 @@ class Stack {
 
   /** Push an expression onto the stack. */
   def push(expr: mw.Expr, src: Register): AsmLine = {
-    stack += expr -> StackValue(src.size, sizeBytes)
+    stack += expr -> StackValue(expr.ty.size, sizeBytes)
     Push(src)
   }
 
@@ -81,7 +81,7 @@ class Stack {
 
   /** Get an MemLocation for a variable in the stack. */
   def accessVar(ident: mw.Ident): MemLocation =
-    MemLocation(RSP, sizeBytes - stack(ident).bottom)
+    MemLocation(RSP, sizeBytes - stack(ident).bottom, opSize = Some(stack(ident).size))
 
   def contains(ident: mw.Ident): Boolean = stack.contains(ident)
   def head: MemLocation = MemLocation(RSP, opSize = Some(stack.last._2.size))