Prohibit inner scope type definition

compiler/erg_compiler/build_hir.rs

@@ -13,7 +13,6 @@ use crate::hir::HIR;
 use crate::lower::ASTLowerer;
 use crate::mod_cache::SharedModuleCache;
 use crate::ownercheck::OwnershipChecker;
-use crate::reorder::Reorderer;
 
 /// Summarize lowering, side-effect checking, and ownership checking
 #[derive(Debug)]
@@ -99,9 +98,6 @@ impl HIRBuilder {
     pub fn build(&mut self, src: String, mode: &str) -> Result<HIR, CompileErrors> {
         let mut ast_builder = ASTBuilder::new(self.cfg().copy());
         let ast = ast_builder.build(src)?;
-        let ast = Reorderer::new()
-            .reorder(ast)
-            .map_err(|errs| self.convert(errs))?;
         let hir = self.check(ast, mode)?;
         Ok(hir)
     }

compiler/erg_compiler/error.rs

@@ -1296,6 +1296,24 @@ passed keyword args:    {RED}{kw_args_len}{RESET}"
     pub fn file_error(errno: usize, desc: String, loc: Location, caused_by: AtomicStr) -> Self {
         Self::new(ErrorCore::new(errno, IoError, loc, desc, None), caused_by)
     }
+
+    pub fn inner_typedef_error(errno: usize, loc: Location, caused_by: AtomicStr) -> Self {
+        Self::new(
+            ErrorCore::new(
+                errno,
+                TypeError,
+                loc,
+                switch_lang!(
+                    "japanese" => format!("型はトップレベルで定義されなければなりません"),
+                    "simplified_chinese" => format!("类型必须在顶层定义"),
+                    "traditional_chinese" => format!("類型必須在頂層定義"),
+                    "english" => format!("types must be defined at the top level"),
+                ),
+                None,
+            ),
+            caused_by,
+        )
+    }
 }
 
 #[derive(Debug)]

compiler/erg_compiler/lower.rs

@@ -30,6 +30,7 @@ use crate::error::{
 use crate::hir;
 use crate::hir::HIR;
 use crate::mod_cache::SharedModuleCache;
+use crate::reorder::Reorderer;
 use crate::varinfo::VarKind;
 use Visibility::*;
 
@@ -533,6 +534,14 @@ impl ASTLowerer {
 
     fn lower_def(&mut self, def: ast::Def) -> LowerResult<hir::Def> {
         log!(info "entered {}({})", fn_name!(), def.sig);
+        if def.def_kind().is_class_or_trait() && self.ctx.kind != ContextKind::Module {
+            self.ctx.decls.remove(def.sig.ident().unwrap().inspect());
+            return Err(LowerError::inner_typedef_error(
+                line!() as usize,
+                def.loc(),
+                self.ctx.caused_by(),
+            ));
+        }
         let name = if let Some(name) = def.sig.name_as_str() {
             name
         } else {
@@ -589,7 +598,6 @@ impl ASTLowerer {
             }
         }
         let id = body.id;
-        // TODO: cover all VarPatterns
         self.ctx
             .outer
             .as_mut()
@@ -994,6 +1002,7 @@ impl ASTLowerer {
     pub fn lower(&mut self, ast: AST, mode: &str) -> Result<(HIR, LowerWarnings), LowerErrors> {
         log!(info "the AST lowering process has started.");
         log!(info "the type-checking process has started.");
+        let ast = Reorderer::new().reorder(ast)?;
         let mut module = hir::Module::with_capacity(ast.module.len());
         self.ctx.preregister(ast.module.block())?;
         for chunk in ast.module.into_iter() {

compiler/erg_parser/ast.rs

@@ -2842,6 +2842,7 @@ pub enum DefKind {
     Subsume,
     StructuralTrait,
     Module,
+    /// type alias included
     Other,
 }
 
@@ -2850,6 +2851,14 @@ impl DefKind {
         matches!(self, Self::Trait | Self::Subsume | Self::StructuralTrait)
     }
 
+    pub const fn is_class(&self) -> bool {
+        matches!(self, Self::Class | Self::Inherit)
+    }
+
+    pub const fn is_class_or_trait(&self) -> bool {
+        self.is_class() || self.is_trait()
+    }
+
     pub fn is_module(&self) -> bool {
         matches!(self, Self::Module)
     }