fix: captured refs create scope boundaries in type inference

Author: zharinov

crates/plotnik-lib/src/analyze/type_check/infer.rs

@@ -348,9 +348,16 @@ impl<'a, 'd> InferenceVisitor<'a, 'd> {
     }
 
     /// Determines if an expression creates a scope boundary when captured.
+    ///
+    /// When captured, these expressions produce structured values (not nodes):
+    /// - Sequences/alternations: produce structs/enums from their internal captures
+    /// - Refs: produce whatever the called definition returns (struct if it has captures)
+    ///
+    /// This only affects captured expressions. Uncaptured refs remain transparent
+    /// (their captures bubble up) because this check only runs in `infer_captured_expr`.
     fn inner_creates_scope(inner: &Expr) -> bool {
         match inner {
-            Expr::SeqExpr(_) | Expr::AltExpr(_) => true,
+            Expr::SeqExpr(_) | Expr::AltExpr(_) | Expr::Ref(_) => true,
             Expr::QuantifiedExpr(q) => {
                 // Look through quantifier to the actual expression
                 q.inner()

crates/plotnik-lib/src/emit/snapshots/plotnik_lib__emit__codegen_tests__definitions_nested_capture.snap

@@ -21,15 +21,14 @@ S8 "parent"
 [type_defs]
 T0 = <Node>
 T1 = Struct  M0:1  ; { name }
-T2 = Struct  M1:2  ; { name, item }
+T2 = Struct  M1:1  ; { item }
 T3 = ArrayStar(T2)  ; T2*
-T4 = Struct  M3:1  ; { items }
+T4 = Struct  M2:1  ; { items }
 
 [type_members]
 M0: S1 → T0  ; name: <Node>
-M1: S1 → T0  ; name: <Node>
-M2: S2 → T0  ; item: <Node>
-M3: S3 → T3  ; items: T3
+M1: S2 → T1  ; item: Inner
+M2: S3 → T3  ; items: T3
 
 [type_names]
 N0: S4 → T1  ; Inner
@@ -57,14 +56,14 @@ Outer:
   14   !   (parent)                         15
   15   ε   [Arr]                            17
   17   ε                                    41, 29
-  19   ε   [EndArr Set(M3)]                 21
+  19   ε   [EndArr Set(M2)]                 21
   21   △                                    27
   22   ε   [EndObj Push]                    24
   24   ε                                    47, 19
   26                                        ▶
   27   ε   [EndObj]                         26
-  29   ε   [EndArr Set(M3)]                 27
-  31   ε   [Set(M2)]                        22
+  29   ε   [EndArr Set(M2)]                 27
+  31   ε   [Set(M1)]                        22
   33   !   (Inner)                          01 : 31
   34   ε   [Obj]                            33
   36   ▷                                    39

crates/plotnik-lib/src/emit/snapshots/plotnik_lib__emit__codegen_tests__quantifiers_sequence_in_called_def.snap

@@ -22,15 +22,14 @@ S8 "parent"
 [type_defs]
 T0 = <Node>
 T1 = Struct  M0:1  ; { name }
-T2 = Struct  M1:2  ; { name, item }
+T2 = Struct  M1:1  ; { item }
 T3 = ArrayStar(T2)  ; T2*
-T4 = Struct  M3:1  ; { items }
+T4 = Struct  M2:1  ; { items }
 
 [type_members]
 M0: S1 → T0  ; name: <Node>
-M1: S1 → T0  ; name: <Node>
-M2: S2 → T0  ; item: <Node>
-M3: S3 → T3  ; items: T3
+M1: S2 → T1  ; item: Item
+M2: S3 → T3  ; items: T3
 
 [type_names]
 N0: S4 → T1  ; Item
@@ -68,8 +67,8 @@ Test:
   23   ε                                    46, 28
   25                                        ▶
   26   ε   [EndObj]                         25
-  28   ε   [EndArr Set(M3)]                 26
-  30   ε   [Set(M2)]                        21
+  28   ε   [EndArr Set(M2)]                 26
+  30   ε   [Set(M1)]                        21
   32   !   (Item)                           01 : 30
   33   ε   [Obj]                            32
   35   ▷                                    38