From 01c10f3f5eefb0473cce3a0cdd381b6db39cf1bb Mon Sep 17 00:00:00 2001
From: gingerBill <gingerBill@users.noreply.github.com>
Date: Fri, 26 Sep 2025 10:18:46 +0100
Subject: [PATCH] Use `RecursiveMutex` to fix a race condition with parapoly
 records

---
 src/check_expr.cpp | 10 +++++++---
 src/check_type.cpp |  5 +++--
 src/checker.hpp    |  2 +-
 src/entity.cpp     |  1 +
 src/types.cpp      |  6 ++++--
 5 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/src/check_expr.cpp b/src/check_expr.cpp
index 4462a5907..71d0244d3 100644
--- a/src/check_expr.cpp
+++ b/src/check_expr.cpp
@@ -1293,6 +1293,11 @@ gb_internal void check_assignment(CheckerContext *c, Operand *operand, Type *typ
 						error_line("\t      Got:      %s\n", s_got);
 						gb_string_free(s_got);
 						gb_string_free(s_expected);
+
+						Type *tx = x->Proc.params->Tuple.variables[0]->type;
+						Type *ty = y->Proc.params->Tuple.variables[0]->type;
+						gb_printf_err("%s kind:%.*s e:%p ot:%p\n", type_to_string(tx), LIT(type_strings[tx->kind]), tx->Named.type_name, tx->Named.type_name->TypeName.original_type_for_parapoly);
+						gb_printf_err("%s kind:%.*s e:%p ot:%p\n", type_to_string(ty), LIT(type_strings[ty->kind]), ty->Named.type_name, ty->Named.type_name->TypeName.original_type_for_parapoly);
 					} else {
 						gbString s_expected = type_to_string(y);
 						gbString s_got = type_to_string(x);
@@ -7908,11 +7913,10 @@ gb_internal CallArgumentError check_polymorphic_record_type(CheckerContext *c, O
 
 	{
 		GenTypesData *found_gen_types = ensure_polymorphic_record_entity_has_gen_types(c, original_type);
+		mutex_lock(&found_gen_types->mutex);
+		defer (mutex_unlock(&found_gen_types->mutex));
 
-		rw_mutex_shared_lock(&found_gen_types->mutex);
 		Entity *found_entity = find_polymorphic_record_entity(found_gen_types, param_count, ordered_operands);
-		rw_mutex_shared_unlock(&found_gen_types->mutex);
-
 		if (found_entity) {
 			operand->mode = Addressing_Type;
 			operand->type = found_entity->type;
diff --git a/src/check_type.cpp b/src/check_type.cpp
index 71db34afa..0819de217 100644
--- a/src/check_type.cpp
+++ b/src/check_type.cpp
@@ -312,6 +312,7 @@ gb_internal void add_polymorphic_record_entity(CheckerContext *ctx, Ast *node, T
 		e->state = EntityState_Resolved;
 		e->file = ctx->file;
 		e->pkg = pkg;
+		e->TypeName.original_type_for_parapoly = original_type;
 		add_entity_use(ctx, node, e);
 	}
 
@@ -321,8 +322,8 @@ gb_internal void add_polymorphic_record_entity(CheckerContext *ctx, Ast *node, T
 	e->TypeName.objc_metadata = original_type->Named.type_name->TypeName.objc_metadata;
 
 	auto *found_gen_types = ensure_polymorphic_record_entity_has_gen_types(ctx, original_type);
-	rw_mutex_lock(&found_gen_types->mutex);
-	defer (rw_mutex_unlock(&found_gen_types->mutex));
+	mutex_lock(&found_gen_types->mutex);
+	defer (mutex_unlock(&found_gen_types->mutex));
 
 	for (Entity *prev : found_gen_types->types) {
 		if (prev == e) {
diff --git a/src/checker.hpp b/src/checker.hpp
index d22b99e89..9693c3e38 100644
--- a/src/checker.hpp
+++ b/src/checker.hpp
@@ -417,7 +417,7 @@ struct GenProcsData {
 
 struct GenTypesData {
 	Array<Entity *> types;
-	RwMutex         mutex;
+	RecursiveMutex  mutex;
 };
 
 struct Defineable {
diff --git a/src/entity.cpp b/src/entity.cpp
index e07e882f3..d6d8f58de 100644
--- a/src/entity.cpp
+++ b/src/entity.cpp
@@ -234,6 +234,7 @@ struct Entity {
 		} Variable;
 		struct {
 			Type * type_parameter_specialization;
+			Type * original_type_for_parapoly;
 			String ir_mangled_name;
 			bool   is_type_alias;
 			bool   objc_is_implementation;
diff --git a/src/types.cpp b/src/types.cpp
index 4515b2c60..8604c5363 100644
--- a/src/types.cpp
+++ b/src/types.cpp
@@ -18,8 +18,8 @@ enum BasicKind {
 	Basic_u16,
 	Basic_i32,
 	Basic_u32,
-	Basic_i64,
-	Basic_u64,
+	Basic_i64
+,	Basic_u64,
 	Basic_i128,
 	Basic_u128,
 
@@ -2860,6 +2860,7 @@ gb_internal bool are_types_identical(Type *x, Type *y) {
 		return false;
 	}
 
+	// MUTEX_GUARD(&g_type_mutex);
 	return are_types_identical_internal(x, y, false);
 }
 gb_internal bool are_types_identical_unique_tuples(Type *x, Type *y) {
@@ -2887,6 +2888,7 @@ gb_internal bool are_types_identical_unique_tuples(Type *x, Type *y) {
 		return false;
 	}
 
+	// MUTEX_GUARD(&g_type_mutex);
 	return are_types_identical_internal(x, y, true);
 }