From 56377fc4f8ccbf7e186ac4f6716e54a9b44b05f9 Mon Sep 17 00:00:00 2001
From: David Tolnay <dtolnay@gmail.com>
Date: Sat, 10 Apr 2021 12:18:31 -0700
Subject: Resolve improper ctype lint affecting RustString

---
 src/rust_string.rs | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/src/rust_string.rs b/src/rust_string.rs
index a5fa3f49..77a83f62 100644
--- a/src/rust_string.rs
+++ b/src/rust_string.rs
@@ -1,14 +1,15 @@
 use alloc::string::String;
-use core::mem;
+use core::mem::{self, MaybeUninit};
 
+// ABI compatible with C++ rust::String (not necessarily alloc::string::String).
 #[repr(C)]
 pub struct RustString {
-    repr: String,
+    repr: [MaybeUninit<usize>; mem::size_of::<String>() / mem::size_of::<usize>()],
 }
 
 impl RustString {
     pub fn from(s: String) -> Self {
-        RustString { repr: s }
+        unsafe { mem::transmute::<String, RustString>(s) }
     }
 
     pub fn from_ref(s: &String) -> &Self {
@@ -20,17 +21,18 @@ impl RustString {
     }
 
     pub fn into_string(self) -> String {
-        self.repr
+        unsafe { mem::transmute::<RustString, String>(self) }
     }
 
     pub fn as_string(&self) -> &String {
-        &self.repr
+        unsafe { &*(self as *const RustString as *const String) }
     }
 
     pub fn as_mut_string(&mut self) -> &mut String {
-        &mut self.repr
+        unsafe { &mut *(self as *mut RustString as *mut String) }
     }
 }
 
-const_assert_eq!(mem::size_of::<[usize; 3]>(), mem::size_of::<String>());
-const_assert_eq!(mem::align_of::<usize>(), mem::align_of::<String>());
+const_assert_eq!(mem::size_of::<[usize; 3]>(), mem::size_of::<RustString>());
+const_assert_eq!(mem::size_of::<String>(), mem::size_of::<RustString>());
+const_assert_eq!(mem::align_of::<String>(), mem::align_of::<RustString>());
-- 
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