1 error[E0282]: type annotations needed
2 --> $DIR/issue-16966.rs:2:5
4 LL | panic!(std::default::Default::default());
5 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot infer type of the type parameter `M` declared on the function `begin_panic`
7 = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
8 help: consider specifying the generic argument
9 --> $SRC_DIR/std/src/panic.rs:LL:COL
11 LL | $crate::rt::begin_panic::<M>($msg)
14 error: aborting due to previous error
16 For more information about this error, try `rustc --explain E0282`.