add compile-fail tests; test only on nightly

we'll test on beta when 1.30-beta is out

29 files changed, 488 insertions, 22 deletions

diff --git a/cortex-m-rt/.travis.yml b/cortex-m-rt/.travis.yml
index caa29ef..fd45f63 100644
--- a/cortex-m-rt/.travis.yml
+++ b/cortex-m-rt/.travis.yml
@@ -3,24 +3,29 @@ language: rust
 matrix:
   include:
     - env: TARGET=x86_64-unknown-linux-gnu
-      rust: stable
-      if: (branch = staging OR branch = trying) OR (type = pull_request AND branch = master)
-
-    - env: TARGET=thumbv6m-none-eabi
-      rust: stable
-      if: (branch = staging OR branch = trying) OR (type = pull_request AND branch = master)
-
-    - env: TARGET=thumbv7m-none-eabi
-      rust: stable
-      if: (branch = staging OR branch = trying) OR (type = pull_request AND branch = master)
-
-    - env: TARGET=thumbv7em-none-eabi
-      rust: stable
+      # TODO switch to 1.30-beta
+      rust: nightly
       if: (branch = staging OR branch = trying) OR (type = pull_request AND branch = master)
 
-    - env: TARGET=thumbv7em-none-eabihf
-      rust: stable
-      if: (branch = staging OR branch = trying) OR (type = pull_request AND branch = master)
+      # TODO enable when 1.30-beta is out
+    # - env: TARGET=thumbv6m-none-eabi
+    #   rust: beta
+    #   if: (branch = staging OR branch = trying) OR (type = pull_request AND branch = master)
+
+      # TODO enable when 1.30-beta is out
+    # - env: TARGET=thumbv7m-none-eabi
+    #   rust: beta
+    #   if: (branch = staging OR branch = trying) OR (type = pull_request AND branch = master)
+
+      # TODO enable when 1.30-beta is out
+    # - env: TARGET=thumbv7em-none-eabi
+    #   rust: beta
+    #   if: (branch = staging OR branch = trying) OR (type = pull_request AND branch = master)
+
+      # TODO enable when 1.30-beta is out
+    # - env: TARGET=thumbv7em-none-eabihf
+    #   rust: beta
+    #   if: (branch = staging OR branch = trying) OR (type = pull_request AND branch = master)
 
     - env: TARGET=thumbv6m-none-eabi
       rust: nightly
diff --git a/cortex-m-rt/Cargo.toml b/cortex-m-rt/Cargo.toml
index 016cdc9..9cf2c14 100644
--- a/cortex-m-rt/Cargo.toml
+++ b/cortex-m-rt/Cargo.toml
@@ -15,9 +15,12 @@ r0 = "0.2.1"
 cortex-m-rt-macros = { path = "macros", version = "0.1.0" }
 
 [dev-dependencies]
-panic-semihosting = "0.3.0"
-panic-abort = "0.2.0"
 cortex-m = "0.5.4"
+panic-abort = "0.3.0"
+panic-semihosting = "0.4.0"
+
+[target.'cfg(not(target_os = "none"))'.dev-dependencies]
+compiletest_rs = "0.3.14"
 
 [features]
 device = []
diff --git a/cortex-m-rt/ci/script.sh b/cortex-m-rt/ci/script.sh
index 8443046..0a28641 100644
--- a/cortex-m-rt/ci/script.sh
+++ b/cortex-m-rt/ci/script.sh
@@ -5,7 +5,11 @@ main() {
 
     cargo check --target $TARGET --features device
 
-    ( cd macros && cargo check && cargo test )
+    if [ $TARGET = x86_64-unknown-linux-gnu ]; then
+        ( cd macros && cargo check && cargo test )
+
+        cargo test --test compiletest
+    fi
 
     local examples=(
         alignment
@@ -18,7 +22,7 @@ main() {
     local fail_examples=(
         data_overflow
     )
-    if [ $TRAVIS_RUST_VERSION = nightly ]; then
+    if [ $TARGET != x86_64-unknown-linux-gnu ]; then
         # linking with GNU LD
         for ex in "${examples[@]}"; do
             cargo rustc --target $TARGET --example $ex -- \
diff --git a/cortex-m-rt/macros/src/lib.rs b/cortex-m-rt/macros/src/lib.rs
index 5d6a603..7d3c61a 100644
--- a/cortex-m-rt/macros/src/lib.rs
+++ b/cortex-m-rt/macros/src/lib.rs
@@ -124,6 +124,8 @@ pub fn entry(args: TokenStream, input: TokenStream) -> TokenStream {
         }).collect::<Vec<_>>();
 
     quote!(
+        // TODO(forbid) see tests/compile-fail/entry-hidden.rs
+        // #[forbid(dead_code)]
         #[export_name = "main"]
         #(#attrs)*
         pub fn #ident() -> ! {
@@ -297,7 +299,7 @@ pub fn exception(args: TokenStream, input: TokenStream) -> TokenStream {
                             _ => false,
                         },
                     },
-                "`#DefaultHandler` function must have signature `fn(i16)`"
+                "`DefaultHandler` exception must have signature `fn(i16)`"
             );
 
             let arg = match f.decl.inputs[0] {
@@ -345,7 +347,7 @@ pub fn exception(args: TokenStream, input: TokenStream) -> TokenStream {
                             _ => false,
                         },
                     },
-                "`#[exception(HardFault)]` function must have signature `fn(&ExceptionFrame) -> !`"
+                "`HardFault` exception must have signature `fn(&ExceptionFrame) -> !`"
             );
 
             let arg = match f.decl.inputs[0] {
diff --git a/cortex-m-rt/tests/compile-fail/default-handler-bad-signature-1.rs b/cortex-m-rt/tests/compile-fail/default-handler-bad-signature-1.rs
new file mode 100644
index 0000000..a2c16c1
--- /dev/null
+++ b/cortex-m-rt/tests/compile-fail/default-handler-bad-signature-1.rs
@@ -0,0 +1,16 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_semihosting;
+
+use cortex_m_rt::{entry, exception};
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+#[exception] //~ ERROR custom attribute panicked
+//~^ HELP `DefaultHandler` exception must have signature `fn(i16)`
+fn DefaultHandler(_irqn: i16, undef: u32) {}
diff --git a/cortex-m-rt/tests/compile-fail/default-handler-bad-signature-2.rs b/cortex-m-rt/tests/compile-fail/default-handler-bad-signature-2.rs
new file mode 100644
index 0000000..ec74993
--- /dev/null
+++ b/cortex-m-rt/tests/compile-fail/default-handler-bad-signature-2.rs
@@ -0,0 +1,16 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_semihosting;
+
+use cortex_m_rt::{entry, exception};
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+#[exception] //~ ERROR custom attribute panicked
+//~^ HELP `DefaultHandler` exception must have signature `fn(i16)`
+unsafe fn DefaultHandler(_irqn: i16) {}
diff --git a/cortex-m-rt/tests/compile-fail/default-handler-bad-signature-3.rs b/cortex-m-rt/tests/compile-fail/default-handler-bad-signature-3.rs
new file mode 100644
index 0000000..c827b6a
--- /dev/null
+++ b/cortex-m-rt/tests/compile-fail/default-handler-bad-signature-3.rs
@@ -0,0 +1,18 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_semihosting;
+
+use cortex_m_rt::{entry, exception};
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+#[exception] //~ ERROR custom attribute panicked
+//~^ HELP `DefaultHandler` exception must have signature `fn(i16)`
+fn DefaultHandler(_irqn: i16) -> ! {
+    loop {}
+}
diff --git a/cortex-m-rt/tests/compile-fail/default-handler-hidden.rs b/cortex-m-rt/tests/compile-fail/default-handler-hidden.rs
new file mode 100644
index 0000000..059c10b
--- /dev/null
+++ b/cortex-m-rt/tests/compile-fail/default-handler-hidden.rs
@@ -0,0 +1,22 @@
+// ignore-test :sadface: it's not possible to prevent this user error at compile time
+// see rust-lang/rust#53975 for details
+
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_semihosting;
+
+use cortex_m_rt::{entry, exception};
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+mod hidden {
+    use cortex_m_rt::exception;
+
+    #[exception]
+    fn DefaultHandler(_irqn: i16) {}
+}
diff --git a/cortex-m-rt/tests/compile-fail/default-handler-twice.rs b/cortex-m-rt/tests/compile-fail/default-handler-twice.rs
new file mode 100644
index 0000000..7d6ad98
--- /dev/null
+++ b/cortex-m-rt/tests/compile-fail/default-handler-twice.rs
@@ -0,0 +1,22 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_semihosting;
+
+use cortex_m_rt::{entry, exception};
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+#[exception]
+fn DefaultHandler(_irqn: i16) {}
+
+pub mod reachable {
+    use cortex_m_rt::exception;
+
+    #[exception] //~ ERROR symbol `DefaultHandler` is already defined
+    fn DefaultHandler(_irqn: i16) {}
+}
diff --git a/cortex-m-rt/tests/compile-fail/entry-bad-signature-1.rs b/cortex-m-rt/tests/compile-fail/entry-bad-signature-1.rs
new file mode 100644
index 0000000..c4914db
--- /dev/null
+++ b/cortex-m-rt/tests/compile-fail/entry-bad-signature-1.rs
@@ -0,0 +1,11 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_semihosting;
+
+use cortex_m_rt::entry;
+
+#[entry] //~ ERROR custom attribute panicked
+//~^ HELP `#[entry]` function must have signature `fn() -> !`
+fn foo() {}
diff --git a/cortex-m-rt/tests/compile-fail/entry-bad-signature-2.rs b/cortex-m-rt/tests/compile-fail/entry-bad-signature-2.rs
new file mode 100644
index 0000000..88ffd34
--- /dev/null
+++ b/cortex-m-rt/tests/compile-fail/entry-bad-signature-2.rs
@@ -0,0 +1,11 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_semihosting;
+
+use cortex_m_rt::entry;
+
+#[entry] //~ ERROR custom attribute panicked
+//~^ HELP `#[entry]` function must have signature `fn() -> !`
+fn foo(undef: i32) -> ! {}
diff --git a/cortex-m-rt/tests/compile-fail/entry-bad-signature-3.rs b/cortex-m-rt/tests/compile-fail/entry-bad-signature-3.rs
new file mode 100644
index 0000000..0f2ddca
--- /dev/null
+++ b/cortex-m-rt/tests/compile-fail/entry-bad-signature-3.rs
@@ -0,0 +1,13 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_semihosting;
+
+use cortex_m_rt::entry;
+
+#[entry] //~ ERROR custom attribute panicked
+//~^ HELP `#[entry]` function must have signature `fn() -> !`
+unsafe fn foo() -> ! {
+    loop {}
+}
diff --git a/cortex-m-rt/tests/compile-fail/entry-bad-signature-4.rs b/cortex-m-rt/tests/compile-fail/entry-bad-signature-4.rs
new file mode 100644
index 0000000..2077f41
--- /dev/null
+++ b/cortex-m-rt/tests/compile-fail/entry-bad-signature-4.rs
@@ -0,0 +1,13 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_semihosting;
+
+use cortex_m_rt::entry;
+
+#[entry] //~ ERROR custom attribute panicked
+//~^ HELP `#[entry]` function must have signature `fn() -> !`
+extern "C" fn foo() -> ! {
+    loop {}
+}
diff --git a/cortex-m-rt/tests/compile-fail/entry-hidden.rs b/cortex-m-rt/tests/compile-fail/entry-hidden.rs
new file mode 100644
index 0000000..7d74063
--- /dev/null
+++ b/cortex-m-rt/tests/compile-fail/entry-hidden.rs
@@ -0,0 +1,19 @@
+// ignore-test :sadface: it's not possible to prevent this user error at compile time
+// see rust-lang/rust#53975 for details
+
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_semihosting;
+
+mod hidden {
+    use cortex_m_rt::entry;
+
+    // this function needs to be "reachable" (all modules between it and the crate root must be
+    // `pub`) or linking will fail
+    #[entry]
+    fn foo() -> ! { //~ ERROR function is never used
+        loop {}
+    }
+}
diff --git a/cortex-m-rt/tests/compile-fail/entry-twice.rs b/cortex-m-rt/tests/compile-fail/entry-twice.rs
new file mode 100644
index 0000000..b2819f6
--- /dev/null
+++ b/cortex-m-rt/tests/compile-fail/entry-twice.rs
@@ -0,0 +1,17 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_semihosting;
+
+use cortex_m_rt::entry;
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+#[entry] //~ ERROR symbol `main` is already defined
+fn bar() -> ! {
+    loop {}
+}
diff --git a/cortex-m-rt/tests/compile-fail/exception-bad-signature-1.rs b/cortex-m-rt/tests/compile-fail/exception-bad-signature-1.rs
new file mode 100644
index 0000000..1f4b707
--- /dev/null
+++ b/cortex-m-rt/tests/compile-fail/exception-bad-signature-1.rs
@@ -0,0 +1,16 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_semihosting;
+
+use cortex_m_rt::{entry, exception};
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+#[exception] //~ ERROR custom attribute panicked
+//~^ HELP `#[exception]` functions other than `DefaultHandler` and `HardFault` must have signature `fn()`
+fn SysTick(undef: u32) {}
diff --git a/cortex-m-rt/tests/compile-fail/exception-bad-signature-2.rs b/cortex-m-rt/tests/compile-fail/exception-bad-signature-2.rs
new file mode 100644
index 0000000..8b1011d
--- /dev/null
+++ b/cortex-m-rt/tests/compile-fail/exception-bad-signature-2.rs
@@ -0,0 +1,16 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_semihosting;
+
+use cortex_m_rt::{entry, exception};
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+#[exception] //~ ERROR custom attribute panicked
+//~^ HELP `#[exception]` functions other than `DefaultHandler` and `HardFault` must have signature `fn()`
+unsafe fn SysTick() {}
diff --git a/cortex-m-rt/tests/compile-fail/exception-bad-signature-3.rs b/cortex-m-rt/tests/compile-fail/exception-bad-signature-3.rs
new file mode 100644
index 0000000..546ef90
--- /dev/null
+++ b/cortex-m-rt/tests/compile-fail/exception-bad-signature-3.rs
@@ -0,0 +1,18 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_semihosting;
+
+use cortex_m_rt::{entry, exception};
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+#[exception] //~ ERROR custom attribute panicked
+//~^ HELP `#[exception]` functions other than `DefaultHandler` and `HardFault` must have signature `fn()`
+fn SysTick() -> ! {
+    loop {}
+}
diff --git a/cortex-m-rt/tests/compile-fail/exception-hidden.rs b/cortex-m-rt/tests/compile-fail/exception-hidden.rs
new file mode 100644
index 0000000..053c81c
--- /dev/null
+++ b/cortex-m-rt/tests/compile-fail/exception-hidden.rs
@@ -0,0 +1,22 @@
+// ignore-test :sadface: it's not possible to prevent this user error at compile time
+// see rust-lang/rust#53975 for details
+
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_semihosting;
+
+use cortex_m_rt::{entry, exception};
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+mod hidden {
+    use cortex_m_rt::exception;
+
+    #[exception]
+    fn SysTick() {}
+}
diff --git a/cortex-m-rt/tests/compile-fail/exception-twice.rs b/cortex-m-rt/tests/compile-fail/exception-twice.rs
new file mode 100644
index 0000000..5377fce
--- /dev/null
+++ b/cortex-m-rt/tests/compile-fail/exception-twice.rs
@@ -0,0 +1,22 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_semihosting;
+
+use cortex_m_rt::{entry, exception};
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+#[exception]
+fn SysTick() {}
+
+pub mod reachable {
+    use cortex_m_rt::exception;
+
+    #[exception] //~ ERROR symbol `SysTick` is already defined
+    fn SysTick() {}
+}
diff --git a/cortex-m-rt/tests/compile-fail/hard-fault-bad-signature-1.rs b/cortex-m-rt/tests/compile-fail/hard-fault-bad-signature-1.rs
new file mode 100644
index 0000000..7c61240
--- /dev/null
+++ b/cortex-m-rt/tests/compile-fail/hard-fault-bad-signature-1.rs
@@ -0,0 +1,18 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_semihosting;
+
+use cortex_m_rt::{entry, exception, ExceptionFrame};
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+#[exception] //~ ERROR custom attribute panicked
+//~^ HELP `HardFault` exception must have signature `fn(&ExceptionFrame) -> !`
+fn HardFault(_ef: &ExceptionFrame, undef: u32) -> ! {
+    loop {}
+}
diff --git a/cortex-m-rt/tests/compile-fail/hard-fault-bad-signature-2.rs b/cortex-m-rt/tests/compile-fail/hard-fault-bad-signature-2.rs
new file mode 100644
index 0000000..add6943
--- /dev/null
+++ b/cortex-m-rt/tests/compile-fail/hard-fault-bad-signature-2.rs
@@ -0,0 +1,18 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_semihosting;
+
+use cortex_m_rt::{entry, exception, ExceptionFrame};
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+#[exception] //~ ERROR custom attribute panicked
+//~^ HELP `HardFault` exception must have signature `fn(&ExceptionFrame) -> !`
+unsafe fn HardFault(_ef: &ExceptionFrame) -> ! {
+    loop {}
+}
diff --git a/cortex-m-rt/tests/compile-fail/hard-fault-hidden.rs b/cortex-m-rt/tests/compile-fail/hard-fault-hidden.rs
new file mode 100644
index 0000000..31237c4
--- /dev/null
+++ b/cortex-m-rt/tests/compile-fail/hard-fault-hidden.rs
@@ -0,0 +1,24 @@
+// ignore-test :sadface: it's not possible to prevent this user error at compile time
+// see rust-lang/rust#53975 for details
+
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_semihosting;
+
+use cortex_m_rt::{entry, exception, ExceptionFrame};
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+mod hidden {
+    use cortex_m_rt::{exception, ExceptionFrame};
+
+    #[exception]
+    fn HardFault(_ef: &ExceptionFrame) -> ! {
+        loop {}
+    }
+}
diff --git a/cortex-m-rt/tests/compile-fail/hard-fault-twice.rs b/cortex-m-rt/tests/compile-fail/hard-fault-twice.rs
new file mode 100644
index 0000000..90270e5
--- /dev/null
+++ b/cortex-m-rt/tests/compile-fail/hard-fault-twice.rs
@@ -0,0 +1,26 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_semihosting;
+
+use cortex_m_rt::{entry, exception, ExceptionFrame};
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+#[exception]
+fn HardFault(_ef: &ExceptionFrame) -> ! {
+    loop {}
+}
+
+pub mod reachable {
+    use cortex_m_rt::{exception, ExceptionFrame};
+
+    #[exception] //~ ERROR symbol `UserHardFault` is already defined
+    fn HardFault(_ef: &ExceptionFrame) -> ! {
+        loop {}
+    }
+}
diff --git a/cortex-m-rt/tests/compile-fail/pre-init-bad-signature-1.rs b/cortex-m-rt/tests/compile-fail/pre-init-bad-signature-1.rs
new file mode 100644
index 0000000..58d3022
--- /dev/null
+++ b/cortex-m-rt/tests/compile-fail/pre-init-bad-signature-1.rs
@@ -0,0 +1,16 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_semihosting;
+
+use cortex_m_rt::{entry, pre_init};
+
+#[pre_init] //~ ERROR custom attribute panicked
+//~^ HELP `#[pre_init]` function must have signature `unsafe fn()`
+fn foo() {}
+
+#[entry]
+fn bar() -> ! {
+    loop {}
+}
diff --git a/cortex-m-rt/tests/compile-fail/pre-init-bad-signature-2.rs b/cortex-m-rt/tests/compile-fail/pre-init-bad-signature-2.rs
new file mode 100644
index 0000000..e47ed59
--- /dev/null
+++ b/cortex-m-rt/tests/compile-fail/pre-init-bad-signature-2.rs
@@ -0,0 +1,16 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_semihosting;
+
+use cortex_m_rt::{entry, pre_init};
+
+#[pre_init] //~ ERROR custom attribute panicked
+//~^ HELP `#[pre_init]` function must have signature `unsafe fn()`
+unsafe fn foo(undef: i32) {}
+
+#[entry]
+fn bar() -> ! {
+    loop {}
+}
diff --git a/cortex-m-rt/tests/compile-fail/pre-init-hidden.rs b/cortex-m-rt/tests/compile-fail/pre-init-hidden.rs
new file mode 100644
index 0000000..f512d62
--- /dev/null
+++ b/cortex-m-rt/tests/compile-fail/pre-init-hidden.rs
@@ -0,0 +1,23 @@
+// ignore-test :sadface: it's not possible to prevent this user error at compile time
+// see rust-lang/rust#53975 for details
+
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_semihosting;
+
+mod hidden {
+    use cortex_m_rt::pre_init;
+
+    // this function needs to be "reachable" (all modules between it and the crate root must be
+    // `pub`) or the function will be ignored
+    #[entry]
+    unsafe fn pre_init() {} //~ ERROR function is never used
+}
+
+#[entry]
+fn foo() -> ! {
+    //~ ERROR function is never used
+    loop {}
+}
diff --git a/cortex-m-rt/tests/compile-fail/pre-init-twice.rs b/cortex-m-rt/tests/compile-fail/pre-init-twice.rs
new file mode 100644
index 0000000..5fb1ade
--- /dev/null
+++ b/cortex-m-rt/tests/compile-fail/pre-init-twice.rs
@@ -0,0 +1,18 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_semihosting;
+
+use cortex_m_rt::{entry, pre_init};
+
+#[pre_init]
+unsafe fn foo() {}
+
+#[pre_init] //~ ERROR symbol `__pre_init` is already defined
+unsafe fn bar() {}
+
+#[entry]
+fn baz() -> ! {
+    loop {}
+}
diff --git a/cortex-m-rt/tests/compiletest.rs b/cortex-m-rt/tests/compiletest.rs
new file mode 100644
index 0000000..6cea3ac
--- /dev/null
+++ b/cortex-m-rt/tests/compiletest.rs
@@ -0,0 +1,21 @@
+extern crate compiletest_rs as compiletest;
+
+use std::path::PathBuf;
+
+fn run_mode(mode: &'static str) {
+    let mut config = compiletest::Config::default();
+
+    config.mode = mode.parse().expect("Invalid mode");
+    config.src_base = PathBuf::from(format!("tests/{}", mode));
+    // config.link_deps(); // Populate config.target_rustcflags with dependencies on the path
+    config.target_rustcflags =
+        Some("-L target/debug -L target/debug/deps -C panic=abort".to_owned());
+    // config.clean_rmeta(); // If your tests import the parent crate, this helps with E0464
+
+    compiletest::run_tests(&config);
+}
+
+#[test]
+fn compile_test() {
+    run_mode("compile-fail");
+}