Add test for issue-49544

Author: JohnTitor

src/test/ui/issues/auxiliary/issue-49544.rs

@@ -0,0 +1,7 @@
+#![crate_type = "lib"]
+
+pub fn foo() -> Vec<String> {
+    std::env::args()
+        .skip(1)
+        .collect()
+}

src/test/ui/issues/issue-49544.rs

@@ -0,0 +1,9 @@
+// aux-build:issue-49544.rs
+// check-pass
+
+extern crate issue_49544;
+use issue_49544::foo;
+
+fn main() {
+    let _ = foo();
+}