diff --git a/src/check_expr.cpp b/src/check_expr.cpp
index a0565faaa..0c8bea126 100644
--- a/src/check_expr.cpp
+++ b/src/check_expr.cpp
@@ -87,7 +87,7 @@ void     check_not_tuple                (CheckerContext *c, Operand *operand);
 void     convert_to_typed               (CheckerContext *c, Operand *operand, Type *target_type);
 gbString expr_to_string                 (Ast *expression);
 void     check_proc_body                (CheckerContext *c, Token token, DeclInfo *decl, Type *type, Ast *body);
-void     update_expr_type               (CheckerContext *c, Ast *e, Type *type, bool final);
+void     update_untyped_expr_type       (CheckerContext *c, Ast *e, Type *type, bool final);
 bool     check_is_terminating           (Ast *node, String const &label);
 bool     check_has_break                (Ast *stmt, String const &label, bool implicit);
 void     check_stmt                     (CheckerContext *c, Ast *node, u32 flags);
@@ -215,6 +215,7 @@ bool find_or_generate_polymorphic_procedure(CheckerContext *c, Entity *base_enti
 	//                                                                           //
 	///////////////////////////////////////////////////////////////////////////////
 
+	CheckerInfo *info = c->info;
 
 	if (base_entity == nullptr) {
 		return false;
@@ -224,6 +225,10 @@ bool find_or_generate_polymorphic_procedure(CheckerContext *c, Entity *base_enti
 		return false;
 	}
 
+
+	gb_mutex_lock(&info->gen_procs_mutex);
+	defer (gb_mutex_unlock(&info->gen_procs_mutex));
+
 	String name = base_entity->token.string;
 
 	Type *src = base_type(base_entity->type);
@@ -280,7 +285,6 @@ bool find_or_generate_polymorphic_procedure(CheckerContext *c, Entity *base_enti
 	});
 
 
-	CheckerInfo *info = c->info;
 	CheckerContext nctx = *c;
 
 	Scope *scope = create_scope(c->info, base_entity->scope);
@@ -297,6 +301,8 @@ bool find_or_generate_polymorphic_procedure(CheckerContext *c, Entity *base_enti
 
 	auto *pt = &src->Proc;
 
+
+
 	// NOTE(bill): This is slightly memory leaking if the type already exists
 	// Maybe it's better to check with the previous types first?
 	Type *final_proc_type = alloc_type_proc(scope, nullptr, 0, nullptr, 0, false, pt->calling_convention);
@@ -306,8 +312,6 @@ bool find_or_generate_polymorphic_procedure(CheckerContext *c, Entity *base_enti
 		return false;
 	}
 
-	gb_mutex_lock(&info->gen_procs_mutex);
-	defer (gb_mutex_unlock(&info->gen_procs_mutex));
 	auto *found_gen_procs = map_get(&info->gen_procs, hash_pointer(base_entity->identifier));
 	if (found_gen_procs) {
 		// gb_mutex_lock(&info->gen_procs_mutex);
@@ -632,6 +636,8 @@ i64 check_distance_between_types(CheckerContext *c, Operand *operand, Type *type
 		if (are_types_identical(src, dst)) {
 			return 3;
 		}
+		gb_mutex_lock(&c->checker->poly_proc_mutex);
+		defer (gb_mutex_unlock(&c->checker->poly_proc_mutex));
 		PolyProcData poly_proc_data = {};
 		if (check_polymorphic_procedure_assignment(c, operand, type, operand->expr, &poly_proc_data)) {
 			Entity *e = poly_proc_data.gen_entity;
@@ -2099,8 +2105,8 @@ void check_comparison(CheckerContext *c, Operand *x, Operand *y, TokenKind op) {
 		} else {
 			x->mode = Addressing_Value;
 
-			update_expr_type(c, x->expr, default_type(x->type), true);
-			update_expr_type(c, y->expr, default_type(y->type), true);
+			update_untyped_expr_type(c, x->expr, default_type(x->type), true);
+			update_untyped_expr_type(c, y->expr, default_type(y->type), true);
 
 			i64 size = 0;
 			if (!is_type_untyped(x->type)) size = gb_max(size, type_size_of(x->type));
@@ -2226,18 +2232,14 @@ void check_shift(CheckerContext *c, Operand *x, Operand *y, Ast *node, Type *typ
 
 		TokenPos pos = ast_token(x->expr).pos;
 		if (x_is_untyped) {
-			gb_mutex_lock(&c->info->untyped_mutex);
-			ExprInfo *info = check_get_expr_info(c->info, x->expr);
-			if (info != nullptr) {
-				info->is_lhs = true;
+			if (x->expr != nullptr) {
+				x->expr->tav.is_lhs = true;
 			}
 			x->mode = Addressing_Value;
 			if (type_hint && is_type_integer(type_hint)) {
 				x->type = type_hint;
 			}
 			// x->value = x_val;
-
-			gb_mutex_unlock(&c->info->untyped_mutex);
 			return;
 		}
 	}
@@ -2484,7 +2486,7 @@ void check_cast(CheckerContext *c, Operand *x, Type *type) {
 		if (is_const_expr && !is_type_constant_type(type)) {
 			final_type = default_type(x->type);
 		}
-		update_expr_type(c, x->expr, final_type, true);
+		update_untyped_expr_type(c, x->expr, final_type, true);
 	}
 
 	if (build_context.vet_extra) {
@@ -2920,11 +2922,9 @@ void check_binary_expr(CheckerContext *c, Operand *x, Ast *node, Type *type_hint
 }
 
 
-void update_expr_type(CheckerContext *c, Ast *e, Type *type, bool final) {
+void update_untyped_expr_type(CheckerContext *c, Ast *e, Type *type, bool final) {
 	GB_ASSERT(e != nullptr);
-	gb_mutex_lock(&c->info->untyped_mutex);
-	defer (gb_mutex_unlock(&c->info->untyped_mutex));
-	ExprInfo *old = check_get_expr_info(c->info, e);
+	ExprInfo *old = check_get_expr_info(c, e);
 	if (old == nullptr) {
 		if (type != nullptr && type != t_invalid) {
 			if (e->tav.type == nullptr || e->tav.type == t_invalid) {
@@ -2942,7 +2942,7 @@ void update_expr_type(CheckerContext *c, Ast *e, Type *type, bool final) {
 			// checked at the end of general checking stage.
 			break;
 		}
-		update_expr_type(c, ue->expr, type, final);
+		update_untyped_expr_type(c, ue->expr, type, final);
 	case_end;
 
 	case_ast_node(be, BinaryExpr, e);
@@ -2953,10 +2953,10 @@ void update_expr_type(CheckerContext *c, Ast *e, Type *type, bool final) {
 		if (token_is_comparison(be->op.kind)) {
 			// NOTE(bill): Do nothing as the types are fine
 		} else if (token_is_shift(be->op.kind)) {
-			update_expr_type(c, be->left, type, final);
+			update_untyped_expr_type(c, be->left, type, final);
 		} else {
-			update_expr_type(c, be->left,  type, final);
-			update_expr_type(c, be->right, type, final);
+			update_untyped_expr_type(c, be->left,  type, final);
+			update_untyped_expr_type(c, be->right, type, final);
 		}
 	case_end;
 
@@ -2966,8 +2966,8 @@ void update_expr_type(CheckerContext *c, Ast *e, Type *type, bool final) {
 			break;
 		}
 
-		update_expr_type(c, te->x, type, final);
-		update_expr_type(c, te->y, type, final);
+		update_untyped_expr_type(c, te->x, type, final);
+		update_untyped_expr_type(c, te->y, type, final);
 	case_end;
 
 	case_ast_node(te, TernaryWhenExpr, e);
@@ -2976,12 +2976,12 @@ void update_expr_type(CheckerContext *c, Ast *e, Type *type, bool final) {
 			break;
 		}
 
-		update_expr_type(c, te->x, type, final);
-		update_expr_type(c, te->y, type, final);
+		update_untyped_expr_type(c, te->x, type, final);
+		update_untyped_expr_type(c, te->y, type, final);
 	case_end;
 
 	case_ast_node(pe, ParenExpr, e);
-		update_expr_type(c, pe->expr, type, final);
+		update_untyped_expr_type(c, pe->expr, type, final);
 	case_end;
 	}
 
@@ -2991,7 +2991,7 @@ void update_expr_type(CheckerContext *c, Ast *e, Type *type, bool final) {
 	}
 
 	// We need to remove it and then give it a new one
-	map_remove(&c->info->untyped, hash_node(e));
+	check_remove_expr_info(c, e);
 
 	if (old->is_lhs && !is_type_integer(type)) {
 		gbString expr_str = expr_to_string(e);
@@ -3005,11 +3005,9 @@ void update_expr_type(CheckerContext *c, Ast *e, Type *type, bool final) {
 	add_type_and_value(c->info, e, old->mode, type, old->value);
 }
 
-void update_expr_value(CheckerContext *c, Ast *e, ExactValue value) {
-	ExprInfo *found = nullptr;
-	gb_mutex_lock(&c->info->untyped_mutex);
-	found = check_get_expr_info(c->info, e);
-	gb_mutex_unlock(&c->info->untyped_mutex);
+void update_untyped_expr_value(CheckerContext *c, Ast *e, ExactValue value) {
+	GB_ASSERT(e != nullptr);
+	ExprInfo *found = check_get_expr_info(c, e);
 	if (found) {
 		found->value = value;
 	}
@@ -3072,7 +3070,7 @@ void convert_to_typed(CheckerContext *c, Operand *operand, Type *target_type) {
 		if (is_type_numeric(operand->type) && is_type_numeric(target_type)) {
 			if (x_kind < y_kind) {
 				operand->type = target_type;
-				update_expr_type(c, operand->expr, target_type, false);
+				update_untyped_expr_type(c, operand->expr, target_type, false);
 			}
 		} else if (x_kind != y_kind) {
 			operand->mode = Addressing_Invalid;
@@ -3094,7 +3092,7 @@ void convert_to_typed(CheckerContext *c, Operand *operand, Type *target_type) {
 			if (operand->mode == Addressing_Invalid) {
 				return;
 			}
-			update_expr_value(c, operand->expr, operand->value);
+			update_untyped_expr_value(c, operand->expr, operand->value);
 		} else {
 			switch (operand->type->Basic.kind) {
 			case Basic_UntypedBool:
@@ -3271,7 +3269,7 @@ void convert_to_typed(CheckerContext *c, Operand *operand, Type *target_type) {
 		break;
 	}
 
-	update_expr_type(c, operand->expr, target_type, true);
+	update_untyped_expr_type(c, operand->expr, target_type, true);
 	operand->type = target_type;
 }
 
@@ -4411,9 +4409,10 @@ CALL_ARGUMENT_CHECKER(check_call_arguments_internal) {
 			}
 		} else {
 			// NOTE(bill): Generate the procedure type for this generic instance
-			PolyProcData poly_proc_data = {};
-
 			if (pt->is_polymorphic && !pt->is_poly_specialized) {
+				gb_mutex_lock(&c->checker->poly_proc_mutex);
+
+				PolyProcData poly_proc_data = {};
 				if (find_or_generate_polymorphic_procedure_from_parameters(c, entity, &operands, call, &poly_proc_data)) {
 					gen_entity = poly_proc_data.gen_entity;
 					GB_ASSERT(is_type_proc(gen_entity->type));
@@ -4421,6 +4420,8 @@ CALL_ARGUMENT_CHECKER(check_call_arguments_internal) {
 				} else {
 					err = CallArgumentError_WrongTypes;
 				}
+
+				gb_mutex_unlock(&c->checker->poly_proc_mutex);
 			}
 
 			GB_ASSERT(is_type_proc(final_proc_type));
@@ -4495,7 +4496,7 @@ CALL_ARGUMENT_CHECKER(check_call_arguments_internal) {
 					add_type_info_type(c, o.type);
 					add_type_and_value(c->info, o.expr, Addressing_Value, e->type, exact_value_typeid(o.type));
 				} else if (show_error && is_type_untyped(o.type)) {
-					update_expr_type(c, o.expr, t, true);
+					update_untyped_expr_type(c, o.expr, t, true);
 				}
 
 			}
@@ -4546,7 +4547,7 @@ CALL_ARGUMENT_CHECKER(check_call_arguments_internal) {
 						add_type_info_type(c, o.type);
 						add_type_and_value(c->info, o.expr, Addressing_Value, t, exact_value_typeid(o.type));
 					} else if (show_error && is_type_untyped(o.type)) {
-						update_expr_type(c, o.expr, t, true);
+						update_untyped_expr_type(c, o.expr, t, true);
 					}
 				}
 			}
@@ -4693,6 +4694,7 @@ CALL_ARGUMENT_CHECKER(check_named_call_arguments) {
 
 	Entity *gen_entity = nullptr;
 	if (pt->is_polymorphic && !pt->is_poly_specialized && err == CallArgumentError_None) {
+		gb_mutex_lock(&c->checker->poly_proc_mutex);
 		PolyProcData poly_proc_data = {};
 		if (find_or_generate_polymorphic_procedure_from_parameters(c, entity, &ordered_operands, call, &poly_proc_data)) {
 			gen_entity = poly_proc_data.gen_entity;
@@ -4701,6 +4703,7 @@ CALL_ARGUMENT_CHECKER(check_named_call_arguments) {
 			proc_type = gept;
 			pt = &gept->Proc;
 		}
+		gb_mutex_unlock(&c->checker->poly_proc_mutex);
 	}
 
 
@@ -5039,7 +5042,7 @@ CallArgumentData check_call_arguments(CheckerContext *c, Operand *operand, Type
 			Entity *entity_to_use = data.gen_entity != nullptr ? data.gen_entity : e;
 			add_entity_use(c, ident, entity_to_use);
 			if (entity_to_use != nullptr) {
-				update_expr_type(c, operand->expr, entity_to_use->type, true);
+				update_untyped_expr_type(c, operand->expr, entity_to_use->type, true);
 			}
 			return data;
 		}
@@ -5313,7 +5316,7 @@ CallArgumentData check_call_arguments(CheckerContext *c, Operand *operand, Type
 			Entity *entity_to_use = data.gen_entity != nullptr ? data.gen_entity : e;
 			add_entity_use(c, ident, entity_to_use);
 			if (entity_to_use != nullptr) {
-				update_expr_type(c, operand->expr, entity_to_use->type, true);
+				update_untyped_expr_type(c, operand->expr, entity_to_use->type, true);
 			}
 
 			if (data.gen_entity != nullptr) {
@@ -5346,7 +5349,7 @@ CallArgumentData check_call_arguments(CheckerContext *c, Operand *operand, Type
 		Entity *entity_to_use = data.gen_entity != nullptr ? data.gen_entity : e;
 		add_entity_use(c, ident, entity_to_use);
 		if (entity_to_use != nullptr) {
-			update_expr_type(c, operand->expr, entity_to_use->type, true);
+			update_untyped_expr_type(c, operand->expr, entity_to_use->type, true);
 		}
 
 		if (data.gen_entity != nullptr) {
@@ -5775,6 +5778,7 @@ ExprKind check_call_expr(CheckerContext *c, Operand *operand, Ast *call, Ast *pr
 				operand->type = t_invalid;;
 				return Expr_Expr;
 			}
+			gb_mutex_lock(&c->checker->poly_type_mutex);
 
 			auto err = check_polymorphic_record_type(c, operand, call);
 			if (err == 0) {
@@ -5792,6 +5796,8 @@ ExprKind check_call_expr(CheckerContext *c, Operand *operand, Ast *call, Ast *pr
 				operand->mode = Addressing_Invalid;
 				operand->type = t_invalid;
 			}
+
+			gb_mutex_unlock(&c->checker->poly_type_mutex);
 		} else {
 			gbString str = type_to_string(t);
 			defer (gb_string_free(str));
@@ -5821,7 +5827,7 @@ ExprKind check_call_expr(CheckerContext *c, Operand *operand, Ast *call, Ast *pr
 				operand->type = t;
 				operand->expr = call;
 				if (operand->mode != Addressing_Invalid) {
-					update_expr_type(c, arg, t, false);
+					update_untyped_expr_type(c, arg, t, false);
 				}
 				break;
 			}
@@ -6555,7 +6561,7 @@ ExprKind check_expr_base_internal(CheckerContext *c, Operand *o, Ast *node, Type
 		if (type_hint != nullptr && is_type_untyped(type)) {
 			if (check_cast_internal(c, &x, type_hint) &&
 			    check_cast_internal(c, &y, type_hint)) {
-				update_expr_type(c, node, type_hint, !is_type_untyped(type_hint));
+				update_untyped_expr_type(c, node, type_hint, !is_type_untyped(type_hint));
 				o->type = type_hint;
 			}
 		}
@@ -8251,7 +8257,7 @@ ExprKind check_expr_base(CheckerContext *c, Operand *o, Ast *node, Type *type_hi
 		gb_string_free(xs);
 	}
 	if (o->type != nullptr && is_type_untyped(o->type)) {
-		add_untyped(c->info, node, false, o->mode, o->type, o->value);
+		add_untyped(c, node, o->mode, o->type, o->value);
 	}
 	add_type_and_value(c->info, node, o->mode, o->type, o->value);
 	return kind;
diff --git a/src/check_stmt.cpp b/src/check_stmt.cpp
index 1d7cf3cce..8a7555945 100644
--- a/src/check_stmt.cpp
+++ b/src/check_stmt.cpp
@@ -1103,7 +1103,7 @@ void check_switch_stmt(CheckerContext *ctx, Ast *node, u32 mod_flags) {
 					if (y.mode != Addressing_Constant) {
 						continue;
 					}
-					update_expr_type(ctx, z.expr, x.type, !is_type_untyped(x.type));
+					update_untyped_expr_type(ctx, z.expr, x.type, !is_type_untyped(x.type));
 					add_constant_switch_case(ctx, &seen, y);
 				}
 			}
@@ -1706,7 +1706,7 @@ void check_stmt_internal(CheckerContext *ctx, Ast *node, u32 flags) {
 				Operand *o = &operands[i];
 				check_assignment(ctx, o, e->type, str_lit("return statement"));
 				if (is_type_untyped(o->type)) {
-					update_expr_type(ctx, o->expr, e->type, true);
+					update_untyped_expr_type(ctx, o->expr, e->type, true);
 				}
 			}
 		}
diff --git a/src/checker.cpp b/src/checker.cpp
index 529311baa..b23ac9e2d 100644
--- a/src/checker.cpp
+++ b/src/checker.cpp
@@ -4,7 +4,6 @@
 void check_expr(CheckerContext *c, Operand *operand, Ast *expression);
 void check_expr_or_type(CheckerContext *c, Operand *operand, Ast *expression, Type *type_hint=nullptr);
 void add_comparison_procedures_for_fields(CheckerContext *c, Type *t);
-void check_proc_info(Checker *c, ProcInfo *pi);
 
 
 bool is_operand_value(Operand o) {
@@ -835,7 +834,7 @@ void init_checker_info(CheckerInfo *i) {
 	gbAllocator a = heap_allocator();
 	array_init(&i->definitions,   a);
 	array_init(&i->entities,      a);
-	map_init(&i->untyped,         a);
+	map_init(&i->global_untyped, a);
 	string_map_init(&i->foreigns, a);
 	map_init(&i->gen_procs,       a);
 	map_init(&i->gen_types,       a);
@@ -847,6 +846,7 @@ void init_checker_info(CheckerInfo *i) {
 	array_init(&i->required_foreign_imports_through_force, a);
 	array_init(&i->required_global_variables, a);
 	array_init(&i->testing_procedures, a, 0, 0);
+	mpmc_init(&i->untyped_queue, heap_allocator(), 1<<20);
 
 
 	i->allow_identifier_uses = build_context.query_data_set_settings.kind == QueryDataSet_GoToDefinitions;
@@ -854,7 +854,6 @@ void init_checker_info(CheckerInfo *i) {
 		array_init(&i->identifier_uses, a);
 	}
 
-	gb_mutex_init(&i->untyped_mutex);
 	gb_mutex_init(&i->gen_procs_mutex);
 	gb_mutex_init(&i->gen_types_mutex);
 	gb_mutex_init(&i->type_info_mutex);
@@ -869,7 +868,7 @@ void init_checker_info(CheckerInfo *i) {
 void destroy_checker_info(CheckerInfo *i) {
 	array_free(&i->definitions);
 	array_free(&i->entities);
-	map_destroy(&i->untyped);
+	map_destroy(&i->global_untyped);
 	string_map_destroy(&i->foreigns);
 	map_destroy(&i->gen_procs);
 	map_destroy(&i->gen_types);
@@ -881,8 +880,8 @@ void destroy_checker_info(CheckerInfo *i) {
 	array_free(&i->identifier_uses);
 	array_free(&i->required_foreign_imports_through_force);
 	array_free(&i->required_global_variables);
+	mpmc_destroy(&i->untyped_queue);
 
-	gb_mutex_destroy(&i->untyped_mutex);
 	gb_mutex_destroy(&i->gen_procs_mutex);
 	gb_mutex_destroy(&i->gen_types_mutex);
 	gb_mutex_destroy(&i->type_info_mutex);
@@ -956,6 +955,9 @@ bool init_checker(Checker *c, Parser *parser) {
 	// NOTE(bill): 1 Mi elements should be enough on average
 	mpmc_init(&c->procs_to_check_queue, heap_allocator(), 1<<20);
 	gb_semaphore_init(&c->procs_to_check_semaphore);
+
+	gb_mutex_init(&c->poly_type_mutex);
+	gb_mutex_init(&c->poly_proc_mutex);
 	return true;
 }
 
@@ -1041,13 +1043,23 @@ AstFile *ast_file_of_filename(CheckerInfo *i, String filename) {
 Scope *scope_of_node(Ast *node) {
 	return node->scope;
 }
-ExprInfo *check_get_expr_info(CheckerInfo *i, Ast *expr) {
-	ExprInfo *res = nullptr;
-	ExprInfo **found = map_get(&i->untyped, hash_node(expr));
+ExprInfo *check_get_expr_info(CheckerContext *c, Ast *expr) {
+	UntypedExprInfoMap *untyped = c->untyped ? c->untyped : &c->info->global_untyped;
+	ExprInfo **found = map_get(untyped, hash_pointer(expr));
 	if (found) {
-		res = *found;
+		return *found;
 	}
-	return res;
+	return nullptr;
+}
+
+void check_set_expr_info(CheckerContext *c, Ast *expr, AddressingMode mode, Type *type, ExactValue value) {
+	UntypedExprInfoMap *untyped = c->untyped ? c->untyped : &c->info->global_untyped;
+	map_set(untyped, hash_pointer(expr), make_expr_info(mode, type, value, false));
+}
+
+void check_remove_expr_info(CheckerContext *c, Ast *e) {
+	UntypedExprInfoMap *untyped = c->untyped ? c->untyped : &c->info->global_untyped;
+	map_remove(untyped, hash_pointer(e));
 }
 
 
@@ -1089,19 +1101,21 @@ isize type_info_index(CheckerInfo *info, Type *type, bool error_on_failure) {
 }
 
 
-void add_untyped(CheckerInfo *i, Ast *expression, bool lhs, AddressingMode mode, Type *type, ExactValue value) {
-	if (expression == nullptr) {
+void add_untyped(CheckerContext *c, Ast *expr, AddressingMode mode, Type *type, ExactValue value) {
+	if (expr == nullptr) {
 		return;
 	}
 	if (mode == Addressing_Invalid) {
 		return;
 	}
+
 	if (mode == Addressing_Constant && type == t_invalid) {
 		compiler_error("add_untyped - invalid type: %s", type_to_string(type));
 	}
-	gb_mutex_lock(&i->untyped_mutex);
-	map_set(&i->untyped, hash_node(expression), make_expr_info(mode, type, value, lhs));
-	gb_mutex_unlock(&i->untyped_mutex);
+	if (!is_type_untyped(type)) {
+		return;
+	}
+	check_set_expr_info(c, expr, mode, type, value);
 }
 
 void add_type_and_value(CheckerInfo *i, Ast *expr, AddressingMode mode, Type *type, ExactValue value) {
@@ -3336,12 +3350,14 @@ void check_single_global_entity(Checker *c, Entity *e, DeclInfo *d) {
 }
 
 void check_all_global_entities(Checker *c) {
-	Scope *prev_file = nullptr;
-
 	for_array(i, c->info.entities) {
 		Entity *e = c->info.entities[i];
 		DeclInfo *d = e->decl_info;
 		check_single_global_entity(c, e, d);
+		if (e->type != nullptr && is_type_typed(e->type)) {
+			(void)type_size_of(e->type);
+			(void)type_align_of(e->type);
+		}
 	}
 }
 
@@ -4258,7 +4274,7 @@ void calculate_global_init_order(Checker *c) {
 }
 
 
-void check_proc_info(Checker *c, ProcInfo *pi) {
+void check_proc_info(Checker *c, ProcInfo *pi, UntypedExprInfoMap *untyped) {
 	if (pi == nullptr) {
 		return;
 	}
@@ -4273,6 +4289,7 @@ void check_proc_info(Checker *c, ProcInfo *pi) {
 	defer (destroy_checker_context(&ctx));
 	reset_checker_context(&ctx, pi->file);
 	ctx.decl = pi->decl;
+	ctx.untyped = untyped;
 
 	TypeProc *pt = &pi->type->Proc;
 	String name = pi->token.string;
@@ -4312,24 +4329,21 @@ void check_proc_info(Checker *c, ProcInfo *pi) {
 		pi->decl->entity->flags |= EntityFlag_ProcBodyChecked;
 	}
 	pi->decl->proc_checked = true;
-
+	add_untyped_expressions(&c->info, ctx.untyped);
 }
 
 GB_STATIC_ASSERT(sizeof(isize) == sizeof(void *));
 
-GB_THREAD_PROC(check_proc_info_worker_proc) {
-	if (thread == nullptr) return 0;
-	auto *c = cast(Checker *)thread->user_data;
-	ProcInfo *pi = cast(ProcInfo *)cast(uintptr)thread->user_index;
-	check_proc_info(c, pi);
-	return 0;
-}
-
 void check_unchecked_bodies(Checker *c) {
 	// NOTE(2021-02-26, bill): Sanity checker
 	// This is a partial hack to make sure all procedure bodies have been checked
 	// even ones which should not exist, due to the multithreaded nature of the parser
 	// HACK TODO(2021-02-26, bill): Actually fix this race condition
+
+	UntypedExprInfoMap untyped = {};
+	map_init(&untyped, heap_allocator());
+	defer (map_destroy(&untyped));
+
 	for_array(i, c->info.minimum_dependency_set.entries) {
 		Entity *e = c->info.minimum_dependency_set.entries[i].ptr;
 		if (e == nullptr || e->kind != Entity_Procedure) {
@@ -4355,7 +4369,8 @@ void check_unchecked_bodies(Checker *c) {
 				continue;
 			}
 
-			check_proc_info(c, &pi);
+			map_clear(&untyped);
+			check_proc_info(c, &pi, &untyped);
 		}
 	}
 }
@@ -4399,6 +4414,10 @@ GB_THREAD_PROC(thread_proc_body) {
 	auto *q = &c->procs_to_check_queue;
 	ProcInfo *pi = nullptr;
 
+	UntypedExprInfoMap untyped = {};
+	map_init(&untyped, heap_allocator());
+	defer (map_destroy(&untyped));
+
 	while (proc_bodies_is_running) {
 		gb_semaphore_wait(&c->procs_to_check_semaphore);
 
@@ -4413,7 +4432,8 @@ GB_THREAD_PROC(thread_proc_body) {
 					continue;
 				}
 			}
-			check_proc_info(c, pi);
+			map_clear(&untyped);
+			check_proc_info(c, pi, &untyped);
 		}
 	}
 
@@ -4426,81 +4446,34 @@ void check_procedure_bodies(Checker *c) {
 	auto *q = &c->procs_to_check_queue;
 	ProcInfo *pi = nullptr;
 
-	isize thread_count = gb_max(build_context.thread_count, 1);
-	isize worker_count = thread_count-1; // NOTE(bill): The main thread will also be used for work
-	if (!build_context.threaded_checker) {
-		worker_count = 0;
+	while (mpmc_dequeue(q, &pi)) {
+		GB_ASSERT(pi->decl != nullptr);
+		if (pi->decl->parent && pi->decl->parent->entity) {
+			Entity *parent = pi->decl->parent->entity;
+			// NOTE(bill): Only check a nested procedure if its parent's body has been checked first
+			// This is prevent any possible race conditions in evaluation when multithreaded
+			// NOTE(bill): In single threaded mode, this should never happen
+			if (parent->kind == Entity_Procedure && (parent->flags & EntityFlag_ProcBodyChecked) == 0) {
+				mpmc_enqueue(q, pi);
+				continue;
+			}
+		}
+		check_proc_info(c, pi, nullptr);
 	}
+}
 
-	if (worker_count == 0) {
-		while (mpmc_dequeue(q, &pi)) {
-			if (pi->decl->parent && pi->decl->parent->entity) {
-				Entity *parent = pi->decl->parent->entity;
-				// NOTE(bill): Only check a nested procedure if its parent's body has been checked first
-				// This is prevent any possible race conditions in evaluation when multithreaded
-				// NOTE(bill): In single threaded mode, this should never happen
-				if (parent->kind == Entity_Procedure && (parent->flags & EntityFlag_ProcBodyChecked) == 0) {
-					mpmc_enqueue(q, pi);
-					continue;
-				}
-			}
-			check_proc_info(c, pi);
-		}
-	} else {
-		proc_bodies_is_running = true;
-
-		gbThread threads[64] = {};
-		for (isize i = 0; i < worker_count; i++) {
-			gb_thread_init(threads+i);
-		}
-
-		for (isize i = 0; i < worker_count; i++) {
-			gb_thread_start(threads+i, thread_proc_body, c);
-		}
-
-		while (q->count.load(std::memory_order_relaxed) > 0) {
-			if (mpmc_dequeue(q, &pi)) {
-				if (pi->decl->parent && pi->decl->parent->entity) {
-					Entity *parent = pi->decl->parent->entity;
-					// NOTE(bill): Only check a nested procedure if its parent's body has been checked first
-					// This is prevent any possible race conditions in evaluation when multithreaded
-					// NOTE(bill): In single threaded mode, this should never happen
-					if (parent->kind == Entity_Procedure && (parent->flags & EntityFlag_ProcBodyChecked) == 0) {
-						mpmc_enqueue(q, pi);
-
-						gb_yield();
-						continue;
-					}
-				}
-				check_proc_info(c, pi);
-			}
-
-			gb_yield();
-		}
-
-		proc_bodies_is_running = false;
-		gb_semaphore_post(&c->procs_to_check_semaphore, cast(i32)worker_count);
-
-		gb_yield();
-
-		for (isize i = 0; i < worker_count; i++) {
-			gb_thread_destroy(threads+i);
-		}
-
-		while (mpmc_dequeue(q, &pi)) {
-			if (pi->decl->parent && pi->decl->parent->entity) {
-				Entity *parent = pi->decl->parent->entity;
-				// NOTE(bill): Only check a nested procedure if its parent's body has been checked first
-				// This is prevent any possible race conditions in evaluation when multithreaded
-				// NOTE(bill): In single threaded mode, this should never happen
-				if (parent->kind == Entity_Procedure && (parent->flags & EntityFlag_ProcBodyChecked) == 0) {
-					mpmc_enqueue(q, pi);
-					continue;
-				}
-			}
-			check_proc_info(c, pi);
+void add_untyped_expressions(CheckerInfo *cinfo, UntypedExprInfoMap *untyped) {
+	if (untyped == nullptr) {
+		return;
+	}
+	for_array(i, untyped->entries) {
+		Ast *expr = cast(Ast *)cast(uintptr)untyped->entries[i].key.key;
+		ExprInfo *info = untyped->entries[i].value;
+		if (expr != nullptr && info != nullptr) {
+			mpmc_enqueue(&cinfo->untyped_queue, UntypedExprInfo{expr, info});
 		}
 	}
+	map_clear(untyped);
 }
 
 
@@ -4557,6 +4530,9 @@ void check_parsed_files(Checker *c) {
 	TIME_SECTION("init preload");
 	init_preload(c);
 
+	TIME_SECTION("add global untyped expression to queue");
+	add_untyped_expressions(&c->info, &c->info.global_untyped);
+
 	CheckerContext prev_context = c->builtin_ctx;
 	defer (c->builtin_ctx = prev_context);
 	c->builtin_ctx.decl = make_decl_info(nullptr, nullptr);
@@ -4585,24 +4561,12 @@ void check_parsed_files(Checker *c) {
 
 	TIME_SECTION("add untyped expression values");
 	// Add untyped expression values
-	for_array(i, c->info.untyped.entries) {
-		auto *entry = &c->info.untyped.entries[i];
-		HashKey key = entry->key;
-		Ast *expr = cast(Ast *)cast(uintptr)key.key;
-		ExprInfo *info = entry->value;
-		if (info != nullptr && expr != nullptr) {
-			if (is_type_typed(info->type)) {
-				compiler_error("%s (type %s) is typed!", expr_to_string(expr), type_to_string(info->type));
-			}
-			if (info->mode == Addressing_Constant) {
-			} else if (info->type == t_untyped_nil) {
-			} else if (info->type == t_untyped_undef) {
-			} else if (info->type == t_untyped_bool) {
-			} else {
-				// gb_printf_err("UNTYPED %s %s\n", expr_to_string(expr), type_to_string(info->type));
-			}
-			add_type_and_value(&c->info, expr, info->mode, info->type, info->value);
+	for (UntypedExprInfo u = {}; mpmc_dequeue(&c->info.untyped_queue, &u); /**/) {
+		GB_ASSERT(u.expr != nullptr && u.info != nullptr);
+		if (is_type_typed(u.info->type)) {
+			compiler_error("%s (type %s) is typed!", expr_to_string(u.expr), type_to_string(u.info->type));
 		}
+		add_type_and_value(&c->info, u.expr, u.info->mode, u.info->type, u.info->value);
 	}
 
 	// TODO(bill): Check for unused imports (and remove) or even warn/err
diff --git a/src/checker.hpp b/src/checker.hpp
index b760482ff..98aba8273 100644
--- a/src/checker.hpp
+++ b/src/checker.hpp
@@ -259,6 +259,13 @@ struct AtomOpMapEntry {
 
 struct CheckerContext;
 
+struct UntypedExprInfo {
+	Ast *expr;
+	ExprInfo *info;
+};
+
+typedef Map<ExprInfo *> UntypedExprInfoMap; // Key: Ast *
+
 // CheckerInfo stores all the symbol information for a type-checked program
 struct CheckerInfo {
 	Checker *checker;
@@ -275,6 +282,8 @@ struct CheckerInfo {
 	PtrSet<Entity *>      minimum_dependency_set;
 	PtrSet<isize>         minimum_dependency_type_info_set;
 
+	UntypedExprInfoMap global_untyped; // NOTE(bill): This needs to be a map and not on the Ast
+	                                   // as it needs to be iterated across afterwards
 
 	Array<Entity *> testing_procedures;
 
@@ -282,7 +291,6 @@ struct CheckerInfo {
 	// NOTE(bill): If the semantic checker (check_proc_body) is to ever to be multithreaded,
 	// these variables will be of contention
 
-	gbMutex untyped_mutex;
 	gbMutex gen_procs_mutex;
 	gbMutex gen_types_mutex;
 	gbMutex type_info_mutex;
@@ -292,10 +300,6 @@ struct CheckerInfo {
 	gbMutex foreign_mutex;
 	gbMutex scope_mutex;
 
-	Map<ExprInfo *>       untyped; // Key: Ast * | Expression -> ExprInfo *
-	                               // NOTE(bill): This needs to be a map and not on the Ast
-	                               // as it needs to be iterated across
-
 	Map<Array<Entity *> > gen_procs;       // Key: Ast * | Identifier -> Entity
 	Map<Array<Entity *> > gen_types;       // Key: Type *
 
@@ -311,6 +315,8 @@ struct CheckerInfo {
 
 	Array<Entity *>       required_global_variables;
 	Array<Entity *>       required_foreign_imports_through_force;
+
+	MPMCQueue<UntypedExprInfo> untyped_queue;
 };
 
 struct CheckerContext {
@@ -337,6 +343,8 @@ struct CheckerContext {
 	CheckerPolyPath *poly_path;
 	isize            poly_level; // TODO(bill): Actually handle correctly
 
+	UntypedExprInfoMap *untyped;
+
 #define MAX_INLINE_FOR_DEPTH 1024ll
 	i64 inline_for_depth;
 
@@ -362,6 +370,9 @@ struct Checker {
 
 	MPMCQueue<ProcInfo *> procs_to_check_queue;
 	gbSemaphore procs_to_check_semaphore;
+
+	gbMutex poly_type_mutex;
+	gbMutex poly_proc_mutex;
 };
 
 
@@ -399,9 +410,9 @@ void    scope_lookup_parent (Scope *s, String const &name, Scope **scope_, Entit
 Entity *scope_insert (Scope *s, Entity *entity);
 
 
-ExprInfo *check_get_expr_info     (CheckerInfo *i, Ast *expr);
-void      add_untyped             (CheckerInfo *i, Ast *expression, bool lhs, AddressingMode mode, Type *basic_type, ExactValue value);
 void      add_type_and_value      (CheckerInfo *i, Ast *expression, AddressingMode mode, Type *type, ExactValue value);
+ExprInfo *check_get_expr_info     (CheckerContext *c, Ast *expr);
+void      add_untyped             (CheckerContext *c, Ast *expression, AddressingMode mode, Type *basic_type, ExactValue value);
 void      add_entity_use          (CheckerContext *c, Ast *identifier, Entity *entity);
 void      add_implicit_entity     (CheckerContext *c, Ast *node, Entity *e);
 void      add_entity_and_decl_info(CheckerContext *c, Ast *identifier, Entity *e, DeclInfo *d, bool is_exported=true);
@@ -434,3 +445,5 @@ Type *check_poly_path_pop (CheckerContext *c);
 
 void init_core_context(Checker *c);
 void init_mem_allocator(Checker *c);
+
+void add_untyped_expressions(CheckerInfo *cinfo, UntypedExprInfoMap *untyped);
diff --git a/src/common.cpp b/src/common.cpp
index 211fd4be4..9d528d723 100644
--- a/src/common.cpp
+++ b/src/common.cpp
@@ -27,6 +27,7 @@
 
 #include <math.h>
 #include <string.h>
+#include <atomic> // Because I wanted the C++11 memory order semantics, of which gb.h does not offer (because it was a C89 library)
 
 gb_inline void zero_size(void *ptr, isize len) {
 	memset(ptr, 0, len);
diff --git a/src/llvm_backend.cpp b/src/llvm_backend.cpp
index 95ab55134..d04344c1f 100644
--- a/src/llvm_backend.cpp
+++ b/src/llvm_backend.cpp
@@ -6580,6 +6580,7 @@ lbValue lb_const_value(lbModule *m, Type *type, ExactValue value, bool allow_loc
 				}
 				LLVMValueRef str_len = LLVMConstInt(lb_type(m, t_int), value.value_string.len, true);
 				LLVMValueRef values[2] = {ptr, str_len};
+				GB_ASSERT(is_type_string(original_type));
 
 				res.value = llvm_const_named_struct(lb_type(m, original_type), values, 2);
 			}
diff --git a/src/queue.cpp b/src/queue.cpp
index 048f8fcb9..92d83a76c 100644
--- a/src/queue.cpp
+++ b/src/queue.cpp
@@ -1,5 +1,3 @@
-#include <atomic> // Because I wanted the C++11 memory order semantics, of which gb.h does not offer (because it was a C89 library)
-
 template <typename T>
 struct MPMCQueueNode {
 	T data;
diff --git a/src/timings.cpp b/src/timings.cpp
index 594f6d27e..b1fbdb952 100644
--- a/src/timings.cpp
+++ b/src/timings.cpp
@@ -104,14 +104,14 @@ u64 time_stamp__freq(void) {
 #endif
 }
 
-TimeStamp make_time_stamp(String label) {
+TimeStamp make_time_stamp(String const &label) {
 	TimeStamp ts = {0};
 	ts.start = time_stamp_time_now();
 	ts.label = label;
 	return ts;
 }
 
-void timings_init(Timings *t, String label, isize buffer_size) {
+void timings_init(Timings *t, String const &label, isize buffer_size) {
 	array_init(&t->sections, heap_allocator(), 0, buffer_size);
 	t->total = make_time_stamp(label);
 	t->freq  = time_stamp__freq();
@@ -127,7 +127,8 @@ void timings__stop_current_section(Timings *t) {
 	}
 }
 
-void timings_start_section(Timings *t, String label) {
+void timings_start_section(Timings *t, String const &label) {
+	// gb_printf_err("[%.*s]\n", LIT(label));
 	timings__stop_current_section(t);
 	array_add(&t->sections, make_time_stamp(label));
 }