From ad9ca349dc8e0c17de5636ebd9b17a6a1830d10e Mon Sep 17 00:00:00 2001
From: Swastik Baranwal <swstkbaranwal@gmail.com>
Date: Thu, 29 Dec 2022 03:45:47 +0530
Subject: [PATCH] cgen: fix generics array delete (#16794)

---
 vlib/v/gen/c/fn.v                       | 20 ++++++++++++++++++++
 vlib/v/tests/generics_array_drop_test.v | 11 +++++++++++
 2 files changed, 31 insertions(+)
 create mode 100644 vlib/v/tests/generics_array_drop_test.v

diff --git a/vlib/v/gen/c/fn.v b/vlib/v/gen/c/fn.v
index 58d5364219..f10b8d46b4 100644
--- a/vlib/v/gen/c/fn.v
+++ b/vlib/v/gen/c/fn.v
@@ -959,6 +959,26 @@ fn (mut g Gen) method_call(node ast.CallExpr) {
 		g.expr(node.args[0].expr)
 		g.write(')')
 		return
+	} else if left_sym.kind == .array && node.name == 'drop' {
+		g.write('array_drop(')
+		if left_type.has_flag(.shared_f) {
+			if left_type.is_ptr() {
+				g.write('&')
+			}
+			g.expr(node.left)
+			g.write('->val')
+		} else {
+			if left_type.is_ptr() {
+				g.expr(node.left)
+			} else {
+				g.write('&')
+				g.expr(node.left)
+			}
+		}
+		g.write(', ')
+		g.expr(node.args[0].expr)
+		g.write(')')
+		return
 	}
 
 	if left_sym.kind in [.sum_type, .interface_] {
diff --git a/vlib/v/tests/generics_array_drop_test.v b/vlib/v/tests/generics_array_drop_test.v
new file mode 100644
index 0000000000..529eb0480d
--- /dev/null
+++ b/vlib/v/tests/generics_array_drop_test.v
@@ -0,0 +1,11 @@
+fn shift[T](mut a []T) T {
+	res := a.first()
+	a.drop(1)
+	return res
+}
+
+fn test_generic_array_drop() {
+	mut a := ['x', 'y']
+	assert shift(mut a) == 'x' // 'x'
+	assert a == ['y'] // ['y']
+}