unified: Remove redundant Swift context scopes

With the new context isolation, we don't need to explicitly introduce a
new scope. We could probably get rid of `ctx.scoped` now, but there's no
harm in leaving it around.

Author: tausbn

unified/extractor/src/languages/swift/swift.rs

@@ -48,13 +48,11 @@ impl SwiftContext {
     /// named method so future context fields can opt in or out of
     /// clearing here per-field.
     ///
-    /// Called before recursively translating a body / initializer
-    /// slot. Most rules mutate `ctx` in place — the framework invokes
-    /// each rule with a private clone of the user context, so
-    /// mutations are discarded on rule exit anyway. Rules that need
-    /// the outer context intact *after* the reset-and-translate (see
-    /// e.g. the `property_binding` willSet/didSet rule) wrap the
-    /// mutation in `ctx.scoped(...)` instead.
+    /// Called before recursively translating a body / initializer slot.
+    /// Output-template interpolations each receive a private clone of the user
+    /// context, so resetting one interpolation cannot affect sibling fields.
+    /// Rules can also mutate `ctx` in place when the translation is their last
+    /// use of it, since mutations are discarded on rule exit.
     fn reset(&mut self) {
         *self = SwiftContext::default();
     }
@@ -380,17 +378,13 @@ fn translation_rules() -> Vec<Rule<SwiftContext>> {
                 let mut result = Vec::new();
                 if let Some(val) = val {
                     // Stored property with observers: the initializer is not part
-                    // of the binding, so translate it in a reset scope.
-                    let val = ctx.scoped(|ctx| {
-                        ctx.reset();
-                        ctx.translate(val)
-                    })?;
+                    // of the binding, so translate it with a reset context.
                     result.push(tree!(
                         (variable_declaration
                             modifier: {ctx.outer_modifiers.clone()}
                             pattern: (identifier #{name})
                             type: {ty}
-                            value: {val})
+                            value: {ctx.reset(); val})
                     ));
                 }
                 for acc in accessors.into_iter() {
@@ -750,19 +744,12 @@ fn translation_rules() -> Vec<Rule<SwiftContext>> {
                 trailingClosure: _? @trailing
                 additionalTrailingClosures: _* @additional)
             =>
-            expr {
-                // Always translate the callee in non-pattern context.
-                let callee = ctx.scoped(|ctx| {
-                    ctx.in_pattern = false;
-                    ctx.translate(rawCallee)
-                })?;
-                tree!((call_expr
-                    callee: {callee}
-                    argument: {args}
-                    argument: {trailing.map(|trailing| tree!((argument value: {trailing})))}
-                    argument: {additional}
-                ))
-            }
+            // Always translate the callee in non-pattern context.
+            (call_expr
+                callee: {ctx.in_pattern = false; rawCallee}
+                argument: {args}
+                argument: {trailing.map(|trailing| tree!((argument value: {trailing})))}
+                argument: {additional})
         ),
         // A call or enum-case pattern argument.
         rule!(