From fb338d2a53cd0b9384c3584e78b957af8e745a98 Mon Sep 17 00:00:00 2001
From: Felipe Pena <felipensp@gmail.com>
Date: Sun, 12 Oct 2025 15:56:51 -0300
Subject: [PATCH] markused: fix []T param as used (fix #25383) (#25454)

---
 vlib/v/markused/walker.v                      | 14 +++++++++++
 vlib/v/tests/generic_calls/bug_test.v         |  9 ++++++++
 vlib/v/tests/generic_calls/country.v          |  7 ++++++
 vlib/v/tests/generic_calls/country_cases.v    | 11 +++++++++
 vlib/v/tests/generic_calls/currency.v         |  7 ++++++
 vlib/v/tests/generic_calls/currency_to_code.v |  9 ++++++++
 vlib/v/tests/generic_calls/curreny_cases.v    | 11 +++++++++
 vlib/v/tests/generic_calls/faker.v            | 23 +++++++++++++++++++
 .../tests/generic_calls/faker_country_name.v  |  5 ++++
 .../tests/generic_calls/faker_currency_code.v |  5 ++++
 vlib/v/tests/generic_calls/top_level_domain.v | 12 ++++++++++
 .../generic_calls/top_level_domain_cases.v    | 11 +++++++++
 12 files changed, 124 insertions(+)
 create mode 100644 vlib/v/tests/generic_calls/bug_test.v
 create mode 100644 vlib/v/tests/generic_calls/country.v
 create mode 100644 vlib/v/tests/generic_calls/country_cases.v
 create mode 100644 vlib/v/tests/generic_calls/currency.v
 create mode 100644 vlib/v/tests/generic_calls/currency_to_code.v
 create mode 100644 vlib/v/tests/generic_calls/curreny_cases.v
 create mode 100644 vlib/v/tests/generic_calls/faker.v
 create mode 100644 vlib/v/tests/generic_calls/faker_country_name.v
 create mode 100644 vlib/v/tests/generic_calls/faker_currency_code.v
 create mode 100644 vlib/v/tests/generic_calls/top_level_domain.v
 create mode 100644 vlib/v/tests/generic_calls/top_level_domain_cases.v

diff --git a/vlib/v/markused/walker.v b/vlib/v/markused/walker.v
index 7d280a5b0..e25a252ec 100644
--- a/vlib/v/markused/walker.v
+++ b/vlib/v/markused/walker.v
@@ -1100,6 +1100,20 @@ pub fn (mut w Walker) call_expr(mut node ast.CallExpr) {
 		} else if node.return_type.has_flag(.result) {
 			w.used_result++
 		}
+		if stmt.params.len > 1 && stmt.generic_names.len > 0 {
+			// mark concrete []T param as used
+			for concrete_type_list in w.table.fn_generic_types[node.fkey()] {
+				for k, concrete_type in concrete_type_list {
+					if k >= stmt.params.len - 1 {
+						break
+					}
+					param_typ := stmt.params[k + 1].typ
+					if param_typ.has_flag(.generic) && w.table.type_kind(param_typ) == .array {
+						w.mark_by_type(w.table.find_or_register_array(concrete_type))
+					}
+				}
+			}
+		}
 	}
 }
 
diff --git a/vlib/v/tests/generic_calls/bug_test.v b/vlib/v/tests/generic_calls/bug_test.v
new file mode 100644
index 000000000..4db532ff6
--- /dev/null
+++ b/vlib/v/tests/generic_calls/bug_test.v
@@ -0,0 +1,9 @@
+module main
+
+fn test_main() {
+	mut fake := Faker{}
+
+	code := fake.currency_code()
+	codes := Currency.cases().map(it.to_code())
+	assert codes.contains(code)
+}
diff --git a/vlib/v/tests/generic_calls/country.v b/vlib/v/tests/generic_calls/country.v
new file mode 100644
index 000000000..23d975b06
--- /dev/null
+++ b/vlib/v/tests/generic_calls/country.v
@@ -0,0 +1,7 @@
+module main
+
+pub enum Country {
+	afghanistan
+	albania
+	algeria
+}
diff --git a/vlib/v/tests/generic_calls/country_cases.v b/vlib/v/tests/generic_calls/country_cases.v
new file mode 100644
index 000000000..838c7b527
--- /dev/null
+++ b/vlib/v/tests/generic_calls/country_cases.v
@@ -0,0 +1,11 @@
+module main
+
+pub fn Country.cases() []Country {
+	mut cases := []Country{}
+
+	$for country in Country.values {
+		case := Country.from(country.name) or { panic(err) }
+		cases << case
+	}
+	return cases
+}
diff --git a/vlib/v/tests/generic_calls/currency.v b/vlib/v/tests/generic_calls/currency.v
new file mode 100644
index 000000000..cc77813d1
--- /dev/null
+++ b/vlib/v/tests/generic_calls/currency.v
@@ -0,0 +1,7 @@
+module main
+
+pub enum Currency {
+	afghani
+	argentina_peso
+	aruba_guilder
+}
diff --git a/vlib/v/tests/generic_calls/currency_to_code.v b/vlib/v/tests/generic_calls/currency_to_code.v
new file mode 100644
index 000000000..4988dc942
--- /dev/null
+++ b/vlib/v/tests/generic_calls/currency_to_code.v
@@ -0,0 +1,9 @@
+module main
+
+pub fn (currency Currency) to_code() string {
+	return match currency {
+		.afghani { 'AFN' }
+		.argentina_peso { 'ARS' }
+		.aruba_guilder { 'AWG' }
+	}
+}
diff --git a/vlib/v/tests/generic_calls/curreny_cases.v b/vlib/v/tests/generic_calls/curreny_cases.v
new file mode 100644
index 000000000..b4fb0aad0
--- /dev/null
+++ b/vlib/v/tests/generic_calls/curreny_cases.v
@@ -0,0 +1,11 @@
+module main
+
+pub fn Currency.cases() []Currency {
+	mut cases := []Currency{}
+
+	$for currency in Currency.values {
+		case := Currency.from(currency.name) or { panic(err) }
+		cases << case
+	}
+	return cases
+}
diff --git a/vlib/v/tests/generic_calls/faker.v b/vlib/v/tests/generic_calls/faker.v
new file mode 100644
index 000000000..8a8b4654d
--- /dev/null
+++ b/vlib/v/tests/generic_calls/faker.v
@@ -0,0 +1,23 @@
+module main
+
+import rand.pcg32 { PCG32RNG }
+
+enum Lang {
+	en
+}
+
+pub struct Faker {
+pub mut:
+	lang       Lang = .en
+	randomizer PCG32RNG
+	seeded     bool
+}
+
+pub fn (mut this Faker) random_element[T](elements []T) T {
+	number_of_elements := u64(elements.len)
+	random_index := this.randomizer.u64() % number_of_elements
+
+	return elements[random_index] or {
+		panic('Failed to get random element at index ${random_index} with length ${number_of_elements}.')
+	}
+}
diff --git a/vlib/v/tests/generic_calls/faker_country_name.v b/vlib/v/tests/generic_calls/faker_country_name.v
new file mode 100644
index 000000000..485958ca1
--- /dev/null
+++ b/vlib/v/tests/generic_calls/faker_country_name.v
@@ -0,0 +1,5 @@
+module main
+
+pub fn (mut this Faker) country_name() string {
+	return this.random_element(Country.cases()).str()
+}
diff --git a/vlib/v/tests/generic_calls/faker_currency_code.v b/vlib/v/tests/generic_calls/faker_currency_code.v
new file mode 100644
index 000000000..cd540fab7
--- /dev/null
+++ b/vlib/v/tests/generic_calls/faker_currency_code.v
@@ -0,0 +1,5 @@
+module main
+
+pub fn (mut this Faker) currency_code() string {
+	return this.random_element(Currency.cases()).to_code()
+}
diff --git a/vlib/v/tests/generic_calls/top_level_domain.v b/vlib/v/tests/generic_calls/top_level_domain.v
new file mode 100644
index 000000000..7160577e0
--- /dev/null
+++ b/vlib/v/tests/generic_calls/top_level_domain.v
@@ -0,0 +1,12 @@
+module main
+
+pub enum TopLevelDomain {
+	aaa
+	aarp
+	abb
+	abbott
+	abbvie
+	abc
+	able
+	abogado
+}
diff --git a/vlib/v/tests/generic_calls/top_level_domain_cases.v b/vlib/v/tests/generic_calls/top_level_domain_cases.v
new file mode 100644
index 000000000..c745f48a2
--- /dev/null
+++ b/vlib/v/tests/generic_calls/top_level_domain_cases.v
@@ -0,0 +1,11 @@
+module main
+
+pub fn TopLevelDomain.cases() []TopLevelDomain {
+	mut cases := []TopLevelDomain{}
+
+	$for top_level_domain in TopLevelDomain.values {
+		case := TopLevelDomain.from(top_level_domain.name) or { panic(err) }
+		cases << case
+	}
+	return cases
+}
-- 
2.39.5