Fix scope_for_name to catch NameError properly

src/compile.rs

@@ -1877,7 +1877,9 @@ impl<O: OutputStream> Compiler<O> {
     fn lookup_name(&self, name: &str) -> &Symbol {
         // println!("Looking up {:?}", name);
         let scope = self.scope_stack.last().unwrap();
-        scope.lookup(name).unwrap()
+        scope.lookup(name).expect(
+            "The symbol must be present in the symbol table, even when it is undefined in python.",
+        )
     }
 
     // Low level helper functions:

src/symboltable.rs

@@ -244,13 +244,11 @@ impl SymbolTableBuilder {
             } => {
                 self.scan_expressions(decorator_list)?;
                 self.register_name(name, SymbolRole::Assigned)?;
-
-                self.enter_function(args)?;
-
-                self.scan_statements(body)?;
                 if let Some(expression) = returns {
                     self.scan_expression(expression)?;
                 }
+                self.enter_function(args)?;
+                self.scan_statements(body)?;
                 self.leave_scope();
             }
             ClassDef {