1 files changed, 71 insertions, 0 deletions
diff --git a/src/test/ui/print_type_sizes/generics.rs b/src/test/ui/print_type_sizes/generics.rs
new file mode 100644
index 000000000..3ef7b60db
--- /dev/null
+++ b/src/test/ui/print_type_sizes/generics.rs
@@ -0,0 +1,71 @@
+// compile-flags: -Z print-type-sizes
+// build-pass
+// ignore-pass
+// ^-- needed because `--pass check` does not emit the output needed.
+//     FIXME: consider using an attribute instead of side-effects.
+
+// This file illustrates how generics are handled: types have to be
+// monomorphized, in the MIR of the original function in which they
+// occur, to have their size reported.
+
+#![feature(start)]
+
+// In an ad-hoc attempt to avoid the injection of unwinding code
+// (which clutters the output of `-Z print-type-sizes` with types from
+// `unwind::libunwind`):
+//
+//   * I am not using Default to build values because that seems to
+//     cause the injection of unwinding code. (Instead I just make `fn new`
+//     methods.)
+//
+//   * Pair derive Copy to ensure that we don't inject
+//     unwinding code into generic uses of Pair when T itself is also
+//     Copy.
+//
+//     (I suspect this reflect some naivety within the rust compiler
+//      itself; it should be checking for drop glue, i.e., a destructor
+//      somewhere in the monomorphized types. It should not matter whether
+//      the type is Copy.)
+#[derive(Copy, Clone)]
+pub struct Pair<T> {
+    _car: T,
+    _cdr: T,
+}
+
+impl<T> Pair<T> {
+    fn new(a: T, d: T) -> Self {
+        Pair {
+            _car: a,
+            _cdr: d,
+        }
+    }
+}
+
+#[derive(Copy, Clone)]
+pub struct SevenBytes([u8; 7]);
+pub struct FiftyBytes([u8; 50]);
+
+pub struct ZeroSized;
+
+impl SevenBytes {
+    fn new() -> Self { SevenBytes([0; 7]) }
+}
+
+impl FiftyBytes {
+    fn new() -> Self { FiftyBytes([0; 50]) }
+}
+
+pub fn f1<T:Copy>(x: T) {
+    let _v: Pair<T> = Pair::new(x, x);
+    let _v2: Pair<FiftyBytes> =
+        Pair::new(FiftyBytes::new(), FiftyBytes::new());
+}
+
+#[start]
+fn start(_: isize, _: *const *const u8) -> isize {
+    let _b: Pair<u8> = Pair::new(0, 0);
+    let _s: Pair<SevenBytes> = Pair::new(SevenBytes::new(), SevenBytes::new());
+    let ref _z: ZeroSized = ZeroSized;
+    f1::<SevenBytes>(SevenBytes::new());
+    0
+}