checker: fix a bug in generics array init (#14258)

vlib/v/checker/containers.v

@@ -223,7 +223,7 @@ pub fn (mut c Checker) array_init(mut node ast.ArrayInit) ast.Type {
 }
 
 fn (mut c Checker) check_array_init_para_type(para string, expr ast.Expr, pos token.Pos) {
-	sym := c.table.sym(c.expr(expr))
+	sym := c.table.sym(c.unwrap_generic(c.expr(expr)))
 	if sym.kind !in [.int, .int_literal] {
 		c.error('array $para needs to be an int', pos)
 	}

vlib/v/tests/generics_array_init_test.v

@@ -0,0 +1,44 @@
+fn get_arr_v1<N, T>(num N, val T) []T {
+	return []T{len: num, init: val}
+}
+
+fn get_arr_v2<N, T>(num N, val T) []T {
+	return []T{len: int(num), init: val}
+}
+
+fn get_arr_v3<N, T>(num N, val T) []T {
+	tmp := num
+	return []T{len: tmp, init: val}
+}
+
+fn get_arr_v4<N, T>(num N, val T) []T {
+	tmp := num + 0
+	return []T{len: tmp, init: val}
+}
+
+fn get_arr_v5<N, T>(num N, val T) []T {
+	tmp := 0 + num
+	return []T{len: tmp, init: val}
+}
+
+fn test_generic_array_init() {
+	println(get_arr_v1(2, 'hallo v1'))
+	a1 := get_arr_v1(2, 'hallo v1')
+	assert a1 == ['hallo v1', 'hallo v1']
+
+	println(get_arr_v2(2, 'hallo v2'))
+	a2 := get_arr_v2(2, 'hallo v2')
+	assert a2 == ['hallo v2', 'hallo v2']
+
+	println(get_arr_v3(2, 'hallo v3'))
+	a3 := get_arr_v3(2, 'hallo v3')
+	assert a3 == ['hallo v3', 'hallo v3']
+
+	println(get_arr_v4(2, 'hallo v4'))
+	a4 := get_arr_v4(2, 'hallo v4')
+	assert a4 == ['hallo v4', 'hallo v4']
+
+	println(get_arr_v5(2, 'hallo v5'))
+	a5 := get_arr_v5(2, 'hallo v5')
+	assert a5 == ['hallo v5', 'hallo v5']
+}