Move /src/test to /tests

1 files changed, 169 insertions, 0 deletions

diff --git a/tests/ui/lint/function-item-references.rs b/tests/ui/lint/function-item-references.rs
new file mode 100644
index 00000000000..05213f4ed4b
--- /dev/null
+++ b/tests/ui/lint/function-item-references.rs
@@ -0,0 +1,169 @@
+// check-pass
+#![feature(c_variadic)]
+#![warn(function_item_references)]
+use std::fmt::Pointer;
+use std::fmt::Formatter;
+
+fn nop() { }
+fn foo() -> u32 { 42 }
+fn bar(x: u32) -> u32 { x }
+fn baz(x: u32, y: u32) -> u32 { x + y }
+unsafe fn unsafe_fn() { }
+extern "C" fn c_fn() { }
+unsafe extern "C" fn unsafe_c_fn() { }
+unsafe extern fn variadic(_x: u32, _args: ...) { }
+fn take_generic_ref<'a, T>(_x: &'a T) { }
+fn take_generic_array<T, const N: usize>(_x: [T; N]) { }
+fn multiple_generic<T, U>(_x: T, _y: U) { }
+fn multiple_generic_arrays<T, U, const N: usize, const M: usize>(_x: [T; N], _y: [U; M]) { }
+
+//function references passed to these functions should never lint
+fn call_fn(f: &dyn Fn(u32) -> u32, x: u32) { f(x); }
+fn parameterized_call_fn<F: Fn(u32) -> u32>(f: &F, x: u32) { f(x); }
+
+//function references passed to these functions should lint
+fn print_ptr<F: Pointer>(f: F) { println!("{:p}", f); }
+fn bound_by_ptr_trait<F: Pointer>(_f: F) { }
+fn bound_by_ptr_trait_tuple<F: Pointer, G: Pointer>(_t: (F, G)) { }
+fn implicit_ptr_trait<F>(f: &F) { println!("{:p}", f); }
+
+//case found in tinyvec that triggered a compiler error in an earlier version of the lint checker
+trait HasItem {
+  type Item;
+  fn assoc_item(&self) -> Self::Item;
+}
+fn _format_assoc_item<T: HasItem>(data: T, f: &mut Formatter) -> std::fmt::Result
+    where T::Item: Pointer {
+    //when the arg type bound by `Pointer` is an associated type, we shouldn't attempt to normalize
+    Pointer::fmt(&data.assoc_item(), f)
+}
+
+//simple test to make sure that calls to `Pointer::fmt` aren't double counted
+fn _call_pointer_fmt(f: &mut Formatter) -> std::fmt::Result {
+    let zst_ref = &foo;
+    Pointer::fmt(&zst_ref, f)
+    //~^ WARNING taking a reference to a function item does not give a function pointer
+}
+
+fn main() {
+    //`let` bindings with function references shouldn't lint
+    let _ = &foo;
+    let _ = &mut foo;
+
+    let zst_ref = &foo;
+    let fn_item = foo;
+    let indirect_ref = &fn_item;
+
+    let _mut_zst_ref = &mut foo;
+    let mut mut_fn_item = foo;
+    let _mut_indirect_ref = &mut mut_fn_item;
+
+    let cast_zst_ptr = &foo as *const _;
+    let coerced_zst_ptr: *const _ = &foo;
+
+    let _mut_cast_zst_ptr = &mut foo as *mut _;
+    let _mut_coerced_zst_ptr: *mut _ = &mut foo;
+
+    let _cast_zst_ref = &foo as &dyn Fn() -> u32;
+    let _coerced_zst_ref: &dyn Fn() -> u32 = &foo;
+
+    let _mut_cast_zst_ref = &mut foo as &mut dyn Fn() -> u32;
+    let _mut_coerced_zst_ref: &mut dyn Fn() -> u32 = &mut foo;
+
+    //the suggested way to cast to a function pointer
+    let fn_ptr = foo as fn() -> u32;
+
+    //correct ways to print function pointers
+    println!("{:p}", foo as fn() -> u32);
+    println!("{:p}", fn_ptr);
+
+    //potential ways to incorrectly try printing function pointers
+    println!("{:p}", &foo);
+    //~^ WARNING taking a reference to a function item does not give a function pointer
+    print!("{:p}", &foo);
+    //~^ WARNING taking a reference to a function item does not give a function pointer
+    format!("{:p}", &foo);
+    //~^ WARNING taking a reference to a function item does not give a function pointer
+
+    println!("{:p}", &foo as *const _);
+    //~^ WARNING taking a reference to a function item does not give a function pointer
+    println!("{:p}", zst_ref);
+    //~^ WARNING taking a reference to a function item does not give a function pointer
+    println!("{:p}", cast_zst_ptr);
+    //~^ WARNING taking a reference to a function item does not give a function pointer
+    println!("{:p}", coerced_zst_ptr);
+    //~^ WARNING taking a reference to a function item does not give a function pointer
+
+    println!("{:p}", &fn_item);
+    //~^ WARNING taking a reference to a function item does not give a function pointer
+    println!("{:p}", indirect_ref);
+    //~^ WARNING taking a reference to a function item does not give a function pointer
+
+    println!("{:p}", &nop);
+    //~^ WARNING taking a reference to a function item does not give a function pointer
+    println!("{:p}", &bar);
+    //~^ WARNING taking a reference to a function item does not give a function pointer
+    println!("{:p}", &baz);
+    //~^ WARNING taking a reference to a function item does not give a function pointer
+    println!("{:p}", &unsafe_fn);
+    //~^ WARNING taking a reference to a function item does not give a function pointer
+    println!("{:p}", &c_fn);
+    //~^ WARNING taking a reference to a function item does not give a function pointer
+    println!("{:p}", &unsafe_c_fn);
+    //~^ WARNING taking a reference to a function item does not give a function pointer
+    println!("{:p}", &variadic);
+    //~^ WARNING taking a reference to a function item does not give a function pointer
+    println!("{:p}", &take_generic_ref::<u32>);
+    //~^ WARNING taking a reference to a function item does not give a function pointer
+    println!("{:p}", &take_generic_array::<u32, 4>);
+    //~^ WARNING taking a reference to a function item does not give a function pointer
+    println!("{:p}", &multiple_generic::<u32, f32>);
+    //~^ WARNING taking a reference to a function item does not give a function pointer
+    println!("{:p}", &multiple_generic_arrays::<u32, f32, 4, 8>);
+    //~^ WARNING taking a reference to a function item does not give a function pointer
+    println!("{:p}", &std::env::var::<String>);
+    //~^ WARNING taking a reference to a function item does not give a function pointer
+
+    println!("{:p} {:p} {:p}", &nop, &foo, &bar);
+    //~^ WARNING taking a reference to a function item does not give a function pointer
+    //~^^ WARNING taking a reference to a function item does not give a function pointer
+    //~^^^ WARNING taking a reference to a function item does not give a function pointer
+
+    //using a function reference to call a function shouldn't lint
+    (&bar)(1);
+
+    //passing a function reference to an arbitrary function shouldn't lint
+    call_fn(&bar, 1);
+    parameterized_call_fn(&bar, 1);
+    std::mem::size_of_val(&foo);
+
+    unsafe {
+        //potential ways to incorrectly try transmuting function pointers
+        std::mem::transmute::<_, usize>(&foo);
+        //~^ WARNING taking a reference to a function item does not give a function pointer
+        std::mem::transmute::<_, (usize, usize)>((&foo, &bar));
+        //~^ WARNING taking a reference to a function item does not give a function pointer
+        //~^^ WARNING taking a reference to a function item does not give a function pointer
+        std::mem::transmute::<_, usize>(&take_generic_ref::<u32>);
+        //~^ WARNING taking a reference to a function item does not give a function pointer
+
+        //the correct way to transmute function pointers
+        std::mem::transmute::<_, usize>(foo as fn() -> u32);
+        std::mem::transmute::<_, (usize, usize)>((foo as fn() -> u32, bar as fn(u32) -> u32));
+    }
+
+    //function references as arguments required to be bound by std::fmt::Pointer should lint
+    print_ptr(&bar);
+    //~^ WARNING taking a reference to a function item does not give a function pointer
+    bound_by_ptr_trait(&bar);
+    //~^ WARNING taking a reference to a function item does not give a function pointer
+    bound_by_ptr_trait_tuple((&foo, &bar));
+    //~^ WARNING taking a reference to a function item does not give a function pointer
+    //~^^ WARNING taking a reference to a function item does not give a function pointer
+    implicit_ptr_trait(&bar); // ignore
+
+    //correct ways to pass function pointers as arguments bound by std::fmt::Pointer
+    print_ptr(bar as fn(u32) -> u32);
+    bound_by_ptr_trait(bar as fn(u32) -> u32);
+    bound_by_ptr_trait_tuple((foo as fn() -> u32, bar as fn(u32) -> u32));
+}