Add preinit tests

Author: YuhanLiin

macros/src/lib.rs

@@ -360,7 +360,7 @@ pub fn pre_init(args: TokenStream, input: TokenStream) -> TokenStream {
 
     if !valid_signature {
         return parse::Error::new(
-            f.span(),
+            f.sig.span(),
             "`#[pre_init]` function must have signature `unsafe fn()`",
         )
         .to_compile_error()

macros/tests/ui/preinit_arg.rs

@@ -0,0 +1,11 @@
+#![no_main]
+
+use msp430_rt_macros::{entry, pre_init};
+
+#[entry]
+fn bar() -> ! {
+    loop {}
+}
+
+#[pre_init(arg)]
+unsafe fn foo() {}

macros/tests/ui/preinit_arg.stderr

@@ -0,0 +1,7 @@
+error: This attribute accepts no arguments
+  --> tests/ui/preinit_arg.rs:10:1
+   |
+10 | #[pre_init(arg)]
+   | ^^^^^^^^^^^^^^^^
+   |
+   = note: this error originates in the attribute macro `pre_init` (in Nightly builds, run with -Z macro-backtrace for more info)

macros/tests/ui/preinit_bad_param.rs

@@ -0,0 +1,11 @@
+#![no_main]
+
+use msp430_rt_macros::{entry, pre_init};
+
+#[entry]
+fn bar() -> ! {
+    loop {}
+}
+
+#[pre_init]
+unsafe fn foo(i: u32) {}

macros/tests/ui/preinit_bad_param.stderr

@@ -0,0 +1,5 @@
+error: `#[pre_init]` function must have signature `unsafe fn()`
+  --> tests/ui/preinit_bad_param.rs:11:1
+   |
+11 | unsafe fn foo(i: u32) {}
+   | ^^^^^^^^^^^^^^^^^^^^^

macros/tests/ui/preinit_bad_ret.rs

@@ -0,0 +1,13 @@
+#![no_main]
+
+use msp430_rt_macros::{entry, pre_init};
+
+#[entry]
+fn bar() -> ! {
+    loop {}
+}
+
+#[pre_init]
+unsafe fn foo() -> u32 {
+    3
+}

macros/tests/ui/preinit_bad_ret.stderr

@@ -0,0 +1,5 @@
+error: `#[pre_init]` function must have signature `unsafe fn()`
+  --> tests/ui/preinit_bad_ret.rs:11:1
+   |
+11 | unsafe fn foo() -> u32 {
+   | ^^^^^^^^^^^^^^^^^^^^^^

macros/tests/ui/preinit_safe.rs

@@ -0,0 +1,11 @@
+#![no_main]
+
+use msp430_rt_macros::{entry, pre_init};
+
+#[entry]
+fn bar() -> ! {
+    loop {}
+}
+
+#[pre_init]
+fn foo() {}

macros/tests/ui/preinit_safe.stderr

@@ -0,0 +1,5 @@
+error: `#[pre_init]` function must have signature `unsafe fn()`
+  --> tests/ui/preinit_safe.rs:11:1
+   |
+11 | fn foo() {}
+   | ^^^^^^^^