From e6ede968bd1461ec2f3b4af5428f1ca8ebf9eb77 Mon Sep 17 00:00:00 2001
From: jekky <gh@jekky.dev>
Date: Mon, 12 Aug 2024 22:23:40 +0100
Subject: [PATCH] feat: only allow adding fields to non-sealed native structs

---
 compiler/src/diagnostics.rs | 7 +++++--
 compiler/src/unit.rs        | 3 +++
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/compiler/src/diagnostics.rs b/compiler/src/diagnostics.rs
index b991f48..e227dc2 100644
--- a/compiler/src/diagnostics.rs
+++ b/compiler/src/diagnostics.rs
@@ -62,13 +62,15 @@ pub enum Diagnostic {
     #[error("this cast is redundant, '{0}' is already a '{1}'")]
     RedundantDynCast(Ident, Ident, Span),
     #[error(
-        "'{0}' is a native struct which is not known to have a valid and complete script \
+        "'{0}' is a native struct which is not known to have a complete and valid script \
          definition, passing arguments to its constructor might result in undefined behavior, \
          it should be preferred to construct such types without arguments: 'new {0}()'"
     )]
     NonSealedStructConstruction(Ident, Span),
-    #[error("adding fields to this struct is not permitted")]
+    #[error("adding fields to sealed native structs is not permitted")]
     AddingFieldToSealedStruct(Span),
+    #[error("adding fields to scripted structs is not permitted")]
+    AddingFieldToScriptedStruct(Span),
     #[error("syntax error, expected {0}")]
     SyntaxError(ExpectedSet, Span),
     #[error("{0}")]
@@ -157,6 +159,7 @@ impl Diagnostic {
             | Self::RedundantDynCast(_, _, span)
             | Self::NonSealedStructConstruction(_, span)
             | Self::AddingFieldToSealedStruct(span)
+            | Self::AddingFieldToScriptedStruct(span)
             | Self::CompileError(_, span)
             | Self::SyntaxError(_, span)
             | Self::CteError(_, span) => *span,
diff --git a/compiler/src/unit.rs b/compiler/src/unit.rs
index 16e0c99..09c2ae6 100644
--- a/compiler/src/unit.rs
+++ b/compiler/src/unit.rs
@@ -800,6 +800,9 @@ impl<'a> CompilationUnit<'a> {
                     && SEALED_STRUCTS.contains(&*self.pool.def_name(target_type)?)
                 {
                     self.diagnostics.push(Diagnostic::AddingFieldToSealedStruct(decl.span));
+                } else if class.flags.is_struct() && !class.flags.is_native() {
+                    self.diagnostics
+                        .push(Diagnostic::AddingFieldToScriptedStruct(decl.span));
                 }
 
                 self.define_field(index, target_type, class.flags, visibility, source, scope)?;