From 28483812eac6bf2097a34e8daa7bd8a6f133feaf Mon Sep 17 00:00:00 2001
From: Sofia <sofia@teascade.net>
Date: Mon, 13 Apr 2026 21:45:58 +0300
Subject: [PATCH] Allow implicit cast from char to int

---
 src/casting.cpp     | 13 ++++++++++---
 src/typechecker.cpp |  6 +++++-
 src/types.cpp       | 21 +++++++++++++++++++++
 src/types.h         |  4 ++++
 test.c              |  2 +-
 5 files changed, 41 insertions(+), 5 deletions(-)

diff --git a/src/casting.cpp b/src/casting.cpp
index dc27e14..09596d1 100644
--- a/src/casting.cpp
+++ b/src/casting.cpp
@@ -1,5 +1,6 @@
 
 #include "casting.h"
+#include <iostream>
 
 namespace types {
     std::vector<CastDefinition> create_casts() {
@@ -21,15 +22,21 @@ namespace types {
                         [](codegen::Builder&, std::shared_ptr<Type>, llvm::Value* value) {
                             return value;
                         } });
+                    continue;
                 }
-                else if (target_ty->is_signed()) {
-                    casts.push_back(CastDefinition{ source_ty, target_ty, false,
+
+                bool allow_implicit = false;
+                if (target_ty->size() >= source_ty->size())
+                    allow_implicit = true;
+
+                if (target_ty->is_signed()) {
+                    casts.push_back(CastDefinition{ source_ty, target_ty, allow_implicit,
                         [](codegen::Builder& builder, std::shared_ptr<Type> target, llvm::Value* value) {
                             return builder.builder->CreateSExtOrTrunc(value, target->codegen(builder), "cast");
                         } });
                 }
                 else {
-                    casts.push_back(CastDefinition{ source_ty, target_ty, false,
+                    casts.push_back(CastDefinition{ source_ty, target_ty, allow_implicit,
                         [](codegen::Builder& builder, std::shared_ptr<Type> target, llvm::Value* value) {
                             return builder.builder->CreateZExtOrTrunc(value, target->codegen(builder), "cast");
                         } });
diff --git a/src/typechecker.cpp b/src/typechecker.cpp
index 90849d0..48163c9 100644
--- a/src/typechecker.cpp
+++ b/src/typechecker.cpp
@@ -15,9 +15,13 @@ namespace {
         std::shared_ptr<types::Type> result;
     };
 
-    Result<TypecheckRes, std::string> check_type(typecheck::State& state, std::shared_ptr<types::Type> checked, std::shared_ptr<types::Type> target) {
+    Result<TypecheckRes, std::string> check_type(
+        typecheck::State& state,
+        std::shared_ptr<types::Type> checked,
+        std::shared_ptr<types::Type> target) {
         auto potential_cast = types::find_cast(state.casts, checked, target);
 
+
         if (types::types_equal(checked, target)) {
             return TypecheckRes{ TypecheckResKind::Ok, target };
         }
diff --git a/src/types.cpp b/src/types.cpp
index dde30a8..adc95dd 100644
--- a/src/types.cpp
+++ b/src/types.cpp
@@ -140,6 +140,19 @@ namespace types {
         }
     }
 
+    uint32_t FundamentalType::size() {
+        switch (this->m_ty) {
+        case FundamentalTypeKind::Int:
+            return 32;
+        case FundamentalTypeKind::Bool:
+            return 1;
+        case FundamentalTypeKind::Char:
+            return 8;
+        default:
+            throw std::runtime_error("Invalid type");
+        }
+    }
+
     std::string FunctionType::formatted() {
         std::stringstream out{ "" };
         out << "(";
@@ -170,6 +183,10 @@ namespace types {
         return std::pair(ptr, self);
     }
 
+    uint32_t FunctionType::size() {
+        return 64;
+    }
+
     std::string PointerType::formatted() {
         std::stringstream out{ "" };
         out << this->m_inner->formatted() << "*";
@@ -183,6 +200,10 @@ namespace types {
         );
     }
 
+    uint32_t PointerType::size() {
+        return 64;
+    }
+
     bool types_equal(std::shared_ptr<types::Type> type1, std::shared_ptr<types::Type> type2) {
         if (type1->m_kind != type2->m_kind)
             return false;
diff --git a/src/types.h b/src/types.h
index 0b5bd72..9d012ef 100644
--- a/src/types.h
+++ b/src/types.h
@@ -34,6 +34,7 @@ namespace types {
         virtual llvm::Value* lt(codegen::Builder& builder, llvm::Value* lhs, llvm::Value* rhs);
         virtual llvm::Value* gt(codegen::Builder& builder, llvm::Value* lhs, llvm::Value* rhs);
         virtual bool is_signed();
+        virtual uint32_t size() = 0;
     };
 
     class FundamentalType : public Type {
@@ -49,6 +50,7 @@ namespace types {
         virtual llvm::Value* lt(codegen::Builder& builder, llvm::Value* lhs, llvm::Value* rhs) override;
         virtual llvm::Value* gt(codegen::Builder& builder, llvm::Value* lhs, llvm::Value* rhs) override;
         virtual bool is_signed() override;
+        virtual uint32_t size() override;
     };
 
 
@@ -68,6 +70,7 @@ namespace types {
         virtual llvm::Type* codegen(codegen::Builder& builder) override;
         virtual std::pair<llvm::Value*, std::shared_ptr<Type>> load(codegen::Builder& builder, llvm::Value* ptr) override;
         virtual std::optional<std::shared_ptr<Type>> return_type() override;
+        virtual uint32_t size() override;
     };
 
 
@@ -82,6 +85,7 @@ namespace types {
         virtual std::string formatted() override;
         virtual llvm::Type* codegen(codegen::Builder& builder) override;
         virtual std::pair<llvm::Value*, std::shared_ptr<Type>> load(codegen::Builder& builder, llvm::Value* ptr) override;
+        virtual uint32_t size() override;
     };
 
     bool types_equal(std::shared_ptr<types::Type> type1, std::shared_ptr<types::Type> type2);
diff --git a/test.c b/test.c
index c0ea202..42e26d0 100644
--- a/test.c
+++ b/test.c
@@ -10,5 +10,5 @@ int main() {
     printf("10th fibonacci number is %d!", fibonacci(10));
     char res = 0;
     res = 15;
-    return (int)res;
+    return res;
 }
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