From 165b4fd33e411970e02f01e90e3b79d85d2515ba Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@medvednikov.com>
Date: Tue, 14 Apr 2026 12:45:23 +0300
Subject: [PATCH] cgen: C error when asserting value from `sql db { select
 from...}` (fixes #23345)

---
 vlib/v/gen/c/if.v                             |  6 +++++
 vlib/v/gen/c/sql_assert_temp_var_test.v       | 18 +++++++++++++
 .../assert_sql_select_sub_array_field.vv      | 27 +++++++++++++++++++
 3 files changed, 51 insertions(+)
 create mode 100644 vlib/v/gen/c/sql_assert_temp_var_test.v
 create mode 100644 vlib/v/gen/c/testdata/assert_sql_select_sub_array_field.vv

diff --git a/vlib/v/gen/c/if.v b/vlib/v/gen/c/if.v
index f81644404..fe04c1d8d 100644
--- a/vlib/v/gen/c/if.v
+++ b/vlib/v/gen/c/if.v
@@ -109,6 +109,9 @@ fn (mut g Gen) need_tmp_var_in_expr(expr ast.Expr) bool {
 			if expr.or_expr.kind != .absent {
 				return true
 			}
+			if g.need_tmp_var_in_expr(expr.left) {
+				return true
+			}
 			if g.need_tmp_var_in_expr(expr.index) {
 				return true
 			}
@@ -182,6 +185,9 @@ fn (mut g Gen) need_tmp_var_in_expr(expr ast.Expr) bool {
 			sym := g.table.sym(expr.typ)
 			return sym.info is ast.Struct && sym.info.has_option
 		}
+		ast.SqlExpr {
+			return true
+		}
 		else {}
 	}
 	return false
diff --git a/vlib/v/gen/c/sql_assert_temp_var_test.v b/vlib/v/gen/c/sql_assert_temp_var_test.v
new file mode 100644
index 000000000..dffe3e521
--- /dev/null
+++ b/vlib/v/gen/c/sql_assert_temp_var_test.v
@@ -0,0 +1,18 @@
+import os
+
+const sql_assert_temp_var_vexe = @VEXE
+
+const sql_assert_temp_var_vroot = os.real_path(@VMODROOT)
+
+const sql_assert_temp_var_testdata = os.join_path(sql_assert_temp_var_vroot, 'vlib/v/gen/c/testdata/assert_sql_select_sub_array_field.vv')
+
+fn test_assert_with_inline_sql_select_compiles() {
+	os.chdir(sql_assert_temp_var_vroot) or {}
+	output_path := os.join_path(os.vtmp_dir(), 'assert_sql_select_sub_array_field.exe')
+	defer {
+		os.rm(output_path) or {}
+	}
+	cmd := '${os.quoted_path(sql_assert_temp_var_vexe)} -o ${os.quoted_path(output_path)} ${os.quoted_path(sql_assert_temp_var_testdata)}'
+	compilation := os.execute(cmd)
+	assert compilation.exit_code == 0, '${cmd}\n${compilation.output}'
+}
diff --git a/vlib/v/gen/c/testdata/assert_sql_select_sub_array_field.vv b/vlib/v/gen/c/testdata/assert_sql_select_sub_array_field.vv
new file mode 100644
index 000000000..752ccd5f5
--- /dev/null
+++ b/vlib/v/gen/c/testdata/assert_sql_select_sub_array_field.vv
@@ -0,0 +1,27 @@
+import db.sqlite
+
+struct Parent {
+	id       int     @[primary; sql: serial]
+	children []Child @[fkey: 'parent_id']
+}
+
+struct Child {
+	id        int @[primary; sql: serial]
+	parent_id int
+}
+
+fn main() {
+	mut db := sqlite.connect(':memory:')!
+	parent := Parent{
+		children: [Child{}, Child{}]
+	}
+	sql db {
+		create table Child
+		create table Parent
+		insert parent into Parent
+	}!
+
+	assert parent.children.len == (sql db {
+		select from Parent limit 1
+	}!)[0].children.len
+}
-- 
2.39.5