Fix: avoid node overriding and re-instantiate a same function (#198)

* fix: avoid re-instantiate functions/methods

* fix: monomorphized expr shouldn't override existing nodes

* fix: refactor function instantiation and always check the resolved qualified name

src/mast/ast.rs

@@ -8,15 +8,10 @@ use super::MastCtx;
 impl Expr {
     /// Convert an expression to another expression, with the same span and a regenerated node id.
     pub fn to_mast<B: Backend>(&self, ctx: &mut MastCtx<B>, kind: &ExprKind) -> Expr {
-        match ctx.generic_func_scope {
-            // not in any generic function scope
-            Some(0) => self.clone(),
-            // in a generic function scope
-            _ => Expr {
-                node_id: ctx.next_node_id(),
-                kind: kind.clone(),
-                ..self.clone()
-            },
+        Expr {
+            node_id: ctx.next_node_id(),
+            kind: kind.clone(),
+            ..self.clone()
         }
     }
 }