Replace checked slice indexing by unchecked to support panic-free code

Eugene Shamis · Eugene Shamis · commit 581aa8d587f4 · 2024-11-04T12:36:24.000-05:00
Fixes rust-lang#126425 Replace the potentially panicking `[]` indexing with `get_unchecked()` to prevent linking with panic-related code.
diff --git a/core/src/fmt/num.rs b/core/src/fmt/num.rs
@@ -88,7 +88,9 @@ unsafe trait GenericRadix: Sized {
                 };
             }
         }
-        let buf = &buf[curr..];
+        // SAFETY: `curr` is initialized to `buf.len()` and is only decremented,
+        // so it is always in bounds.
+        let buf = unsafe { buf.get_unchecked(curr..) };
         // SAFETY: The only chars in `buf` are created by `Self::digit` which are assumed to be
         // valid UTF-8
         let buf = unsafe {

Original file line number	Diff line number	Diff line change
`@@ -88,7 +88,9 @@ unsafe trait GenericRadix: Sized {`
`88`	`88`	`};`
`89`	`89`	`}`
`90`	`90`	`}`
`91`		`- let buf = &buf[curr..];`
	`91`	+ // SAFETY: `curr` is initialized to `buf.len()` and is only decremented,
	`92`	`+ // so it is always in bounds.`
	`93`	`+ let buf = unsafe { buf.get_unchecked(curr..) };`
`92`	`94`	// SAFETY: The only chars in `buf` are created by `Self::digit` which are assumed to be
`93`	`95`	`// valid UTF-8`
`94`	`96`	`let buf = unsafe {`