checker: fix generic array delete in skip_unused mode (#17759)

vlib/v/checker/checker.v

@@ -25,7 +25,7 @@ const (
 
 pub const (
 	array_builtin_methods       = ['filter', 'clone', 'repeat', 'reverse', 'map', 'slice', 'sort',
-		'contains', 'index', 'wait', 'any', 'all', 'first', 'last', 'pop']
+		'contains', 'index', 'wait', 'any', 'all', 'first', 'last', 'pop', 'delete']
 	array_builtin_methods_chk   = token.new_keywords_matcher_from_array_trie(array_builtin_methods)
 	// TODO: remove `byte` from this list when it is no longer supported
 	reserved_type_names         = ['byte', 'bool', 'char', 'i8', 'i16', 'int', 'i64', 'u8', 'u16',

vlib/v/checker/fn.v

@@ -2426,6 +2426,11 @@ fn (mut c Checker) array_builtin_method_call(mut node ast.CallExpr, left_type as
 		} else {
 			node.receiver_type = left_type
 		}
+	} else if method_name == 'delete' {
+		unwrapped_left_sym := c.table.sym(c.unwrap_generic(left_type))
+		if method := c.table.find_method(unwrapped_left_sym, method_name) {
+			node.receiver_type = method.receiver_type
+		}
 	}
 	return node.return_type
 }

vlib/v/tests/skip_unused/generics_array_delete_method.vv

@@ -0,0 +1,16 @@
+struct Bar[K] {
+}
+
+struct Foo[K] {
+mut:
+	bars []Bar[K]
+}
+
+fn main() {
+	mut f := Foo[int]{[Bar[int]{}]}
+	f.xy()
+}
+
+pub fn (mut f Foo[K]) xy() {
+	f.bars.delete(0)
+}