Fix bug in Scope::is_constant.

CHANGELOG.md

@@ -8,6 +8,7 @@ Bug fixes
 ---------
 
 * Invalid property or method access such as `a.b::c.d` or `a.b::func()` no longer panics but properly returns a syntax error.
+* `Scope::is_constant` now returns the correct value.
 
 Enhancements
 ------------

src/types/scope.rs

@@ -375,9 +375,11 @@ impl Scope<'_> {
     /// ```
     #[inline]
     pub fn is_constant(&self, name: &str) -> Option<bool> {
-        self.get_index(name).and_then(|(.., access)| match access {
-            AccessMode::ReadWrite => None,
-            AccessMode::ReadOnly => Some(true),
+        self.get_index(name).and_then(|(.., access)| {
+            Some(match access {
+                AccessMode::ReadWrite => false,
+                AccessMode::ReadOnly => true,
+            })
         })
     }
     /// Update the value of the named entry in the [`Scope`] if it already exists and is not constant.