Change to warn by default / fix typo

compiler/rustc_lint/src/methods.rs

@@ -10,7 +10,7 @@ use rustc_span::{
 
 declare_lint! {
     pub TEMPORARY_CSTRING_AS_PTR,
-    Deny,
+    Warn,
     "detects getting the inner pointer of a temporary `CString`"
 }
 

library/std/src/ffi/c_str.rs

@@ -1265,7 +1265,7 @@ impl CStr {
     /// behavior when `ptr` is used inside the `unsafe` block:
     ///
     /// ```no_run
-    /// # #![allow(unused_must_use)] #![allow(temporary_cstring_as_ptr)]
+    /// # #![allow(unused_must_use, temporary_cstring_as_ptr)]
     /// use std::ffi::CString;
     ///
     /// let ptr = CString::new("Hello").expect("CString::new failed").as_ptr();

src/test/ui/lint/lint-temporary-cstring-as-ptr.rs

@@ -1,4 +1,5 @@
 // ignore-tidy-linelength
+#![deny(temporary_cstring_as_ptr)]
 
 use std::ffi::CString;
 

src/test/ui/lint/lint-temporary-cstring-as-ptr.stderr

@@ -1,12 +1,16 @@
 error: getting the inner pointer of a temporary `CString`
-  --> $DIR/lint-temporary-cstring-as-ptr.rs:6:48
+  --> $DIR/lint-temporary-cstring-as-ptr.rs:7:48
    |
 LL |     let s = CString::new("some text").unwrap().as_ptr();
    |             ---------------------------------- ^^^^^^ this pointer will be invalid
    |             |
    |             this `CString` is deallocated at the end of the expression, bind it to a variable to extend its lifetime
    |
-   = note: `#[deny(temporary_cstring_as_ptr)]` on by default
+note: the lint level is defined here
+  --> $DIR/lint-temporary-cstring-as-ptr.rs:2:9
+   |
+LL | #![deny(temporary_cstring_as_ptr)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^
    = note: pointers do not have a lifetime; when calling `as_ptr` the `CString` is deallocated because nothing is referencing it as far as the type system is concerned
 
 error: aborting due to previous error