From 34f47ddba972e5f697392d30a6c302e93bb0502c Mon Sep 17 00:00:00 2001
From: Jonas Schievink <jonasschievink@gmail.com>
Date: Thu, 16 Jan 2020 22:17:10 +0100
Subject: [PATCH 1/3] Clean up the doc examples in `peripheral`

The Clippy lint was unnecessarily `#[allow]`ed.
---
 src/peripheral/mod.rs | 57 +++++++++++++++++--------------------------
 1 file changed, 22 insertions(+), 35 deletions(-)

diff --git a/src/peripheral/mod.rs b/src/peripheral/mod.rs
index 8854830a..5d7e4736 100644
--- a/src/peripheral/mod.rs
+++ b/src/peripheral/mod.rs
@@ -1,5 +1,4 @@
-#![allow(clippy::needless_doctest_main)]
-//! Core peripherals
+//! Core peripherals.
 //!
 //! # API
 //!
@@ -9,41 +8,32 @@
 //! the [`Peripherals::take`](struct.Peripherals.html#method.take) method.
 //!
 //! ``` no_run
-//! use cortex_m::peripheral::Peripherals;
-//!
-//! fn main() {
-//!     let mut peripherals = Peripherals::take().unwrap();
-//!     peripherals.DWT.enable_cycle_counter();
-//! }
+//! # use cortex_m::peripheral::Peripherals;
+//! let mut peripherals = Peripherals::take().unwrap();
+//! peripherals.DWT.enable_cycle_counter();
 //! ```
 //!
 //! This method can only be successfully called *once* -- this is why the method returns an
 //! `Option`. Subsequent calls to the method will result in a `None` value being returned.
 //!
-//! ``` no_run
-//! use cortex_m::peripheral::Peripherals;
-//!
-//! fn main() {
-//!     let ok = Peripherals::take().unwrap();
-//!     let panics = Peripherals::take().unwrap();
-//! }
+//! ``` no_run, should_panic
+//! # use cortex_m::peripheral::Peripherals;
+//! let ok = Peripherals::take().unwrap();
+//! let panics = Peripherals::take().unwrap();
 //! ```
 //! A part of the peripheral API doesn't require access to a peripheral instance. This part of the
 //! API is provided as static methods on the peripheral types. One example is the
 //! [`DWT::get_cycle_count`](struct.DWT.html#method.get_cycle_count) method.
 //!
 //! ``` no_run
-//! use cortex_m::peripheral::{DWT, Peripherals};
-//!
-//! fn main() {
-//!     {
-//!         let mut peripherals = Peripherals::take().unwrap();
-//!         peripherals.DWT.enable_cycle_counter();
-//!     } // all the peripheral singletons are destroyed here
+//! # use cortex_m::peripheral::{DWT, Peripherals};
+//! {
+//!     let mut peripherals = Peripherals::take().unwrap();
+//!     peripherals.DWT.enable_cycle_counter();
+//! } // all the peripheral singletons are destroyed here
 //!
-//!     // but this method can be called without a DWT instance
-//!     let cyccnt = DWT::get_cycle_count();
-//! }
+//! // but this method can be called without a DWT instance
+//! let cyccnt = DWT::get_cycle_count();
 //! ```
 //!
 //! The singleton property can be *unsafely* bypassed using the `ptr` static method which is
@@ -51,17 +41,14 @@
 //! safe higher level abstractions.
 //!
 //! ``` no_run
-//! use cortex_m::peripheral::{DWT, Peripherals};
-//!
-//! fn main() {
-//!     {
-//!         let mut peripherals = Peripherals::take().unwrap();
-//!         peripherals.DWT.enable_cycle_counter();
-//!     } // all the peripheral singletons are destroyed here
+//! # use cortex_m::peripheral::{DWT, Peripherals};
+//! {
+//!     let mut peripherals = Peripherals::take().unwrap();
+//!     peripherals.DWT.enable_cycle_counter();
+//! } // all the peripheral singletons are destroyed here
 //!
-//!     // actually safe because this is an atomic read with no side effects
-//!     let cyccnt = unsafe { (*DWT::ptr()).cyccnt.read() };
-//! }
+//! // actually safe because this is an atomic read with no side effects
+//! let cyccnt = unsafe { (*DWT::ptr()).cyccnt.read() };
 //! ```
 //!
 //! # References

From 6e63b1e9b94bc08b8cd84383c51b93f6170eb594 Mon Sep 17 00:00:00 2001
From: Jonas Schievink <jonasschievink@gmail.com>
Date: Thu, 16 Jan 2020 22:17:37 +0100
Subject: [PATCH 2/3] Make `Peripherals` `#[non_exhaustive]`

---
 src/peripheral/mod.rs | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/peripheral/mod.rs b/src/peripheral/mod.rs
index 5d7e4736..c9c8ad6e 100644
--- a/src/peripheral/mod.rs
+++ b/src/peripheral/mod.rs
@@ -89,6 +89,7 @@ mod test;
 
 /// Core peripherals
 #[allow(non_snake_case)]
+#[non_exhaustive]
 pub struct Peripherals {
     /// Cache and branch predictor maintenance operations (not present on Cortex-M0 variants)
     pub CBP: CBP,

From d44a5fa86a75a97acef5321d2e061a914cf8d871 Mon Sep 17 00:00:00 2001
From: Jonas Schievink <jonasschievink@gmail.com>
Date: Thu, 16 Jan 2020 23:22:44 +0100
Subject: [PATCH 3/3] Use a private field instead of `#[non_exhaustive]`

---
 src/peripheral/mod.rs | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/peripheral/mod.rs b/src/peripheral/mod.rs
index c9c8ad6e..c84003f0 100644
--- a/src/peripheral/mod.rs
+++ b/src/peripheral/mod.rs
@@ -89,7 +89,6 @@ mod test;
 
 /// Core peripherals
 #[allow(non_snake_case)]
-#[non_exhaustive]
 pub struct Peripherals {
     /// Cache and branch predictor maintenance operations (not present on Cortex-M0 variants)
     pub CBP: CBP,
@@ -126,6 +125,10 @@ pub struct Peripherals {
 
     /// Trace Port Interface Unit (not present on Cortex-M0 variants)
     pub TPIU: TPIU,
+
+    // Private field making `Peripherals` non-exhaustive. We don't use `#[non_exhaustive]` so we
+    // can support older Rust versions.
+    _priv: (),
 }
 
 // NOTE `no_mangle` is used here to prevent linking different minor versions of this crate as that
@@ -188,6 +191,7 @@ impl Peripherals {
             TPIU: TPIU {
                 _marker: PhantomData,
             },
+            _priv: (),
         }
     }
 }