From 3036c73983f7a61b82f34f0613160149ca020926 Mon Sep 17 00:00:00 2001
From: MilkeeyCat <milkeeycat@gmail.com>
Date: Sun, 8 Sep 2024 14:51:32 +0300
Subject: [PATCH] fix: show error when recursive type occurs closes #24

---
 src/passes/type_checker.rs | 21 +++++++++++++++++++++
 src/scope.rs               |  4 ++++
 src/type_table.rs          |  2 +-
 3 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/src/passes/type_checker.rs b/src/passes/type_checker.rs
index 1a75a87..f24ce42 100644
--- a/src/passes/type_checker.rs
+++ b/src/passes/type_checker.rs
@@ -2,6 +2,8 @@ use super::Pass;
 use crate::{
     parser::{Block, Expr, Expression, ParserError, Stmt, UnOp},
     scope::Scope,
+    type_table as tt,
+    type_table::TypeTable,
     types::{Type, TypeError},
 };
 use std::collections::HashSet;
@@ -13,6 +15,7 @@ impl Pass for TypeChecker {
     type Output = Result<()>;
 
     fn proccess(stmts: &mut Vec<Stmt>, scope: &mut Scope) -> Self::Output {
+        Self::check_type_table(scope.type_table(), scope)?;
         for stmt in stmts {
             Self::check_stmt(stmt, scope)?;
         }
@@ -24,6 +27,7 @@ impl Pass for TypeChecker {
 impl TypeChecker {
     fn check_block(block: &Block, scope: &mut Scope) -> Result<()> {
         scope.enter(block.scope.clone());
+        Self::check_type_table(scope.type_table(), scope)?;
         for stmt in &block.statements {
             Self::check_stmt(stmt, scope)?;
         }
@@ -175,4 +179,21 @@ impl TypeChecker {
             _ => {}
         })
     }
+
+    fn check_type_table(type_table: &TypeTable, scope: &Scope) -> Result<()> {
+        for type_ in &type_table.0 {
+            match type_ {
+                tt::Type::Struct(type_struct) => {
+                    for (_, type_) in &type_struct.fields {
+                        Self::check_type(type_, scope)?;
+                        if type_ == &Type::Struct(type_struct.name.clone()) {
+                            panic!("Recursize type {type_} has infinite size");
+                        }
+                    }
+                }
+            }
+        }
+
+        Ok(())
+    }
 }
diff --git a/src/scope.rs b/src/scope.rs
index a9b82a4..c35a585 100644
--- a/src/scope.rs
+++ b/src/scope.rs
@@ -85,6 +85,10 @@ impl Scope {
         &mut self.0.last_mut().unwrap().symbol_table
     }
 
+    pub fn type_table(&self) -> &TypeTable {
+        &self.0.last().unwrap().type_table
+    }
+
     pub fn type_table_mut(&mut self) -> &mut TypeTable {
         &mut self.0.last_mut().unwrap().type_table
     }
diff --git a/src/type_table.rs b/src/type_table.rs
index 18fa900..e344147 100644
--- a/src/type_table.rs
+++ b/src/type_table.rs
@@ -65,7 +65,7 @@ impl TypeStruct {
 }
 
 #[derive(Debug, Clone, PartialEq)]
-pub struct TypeTable(Vec<Type>);
+pub struct TypeTable(pub Vec<Type>);
 
 impl TypeTable {
     pub fn new() -> Self {