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Address diagnostics regression for 'const_char_encode_utf8';
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library/core/src/char/methods.rs

+9-2
Original file line numberDiff line numberDiff line change
@@ -1,6 +1,7 @@
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//! impl char {}
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use super::*;
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use crate::intrinsics::const_eval_select;
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use crate::slice;
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use crate::str::from_utf8_unchecked_mut;
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use crate::unicode::printable::is_printable;
@@ -1762,6 +1763,13 @@ const fn len_utf8(code: u32) -> usize {
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#[doc(hidden)]
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#[inline]
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pub const fn encode_utf8_raw(code: u32, dst: &mut [u8]) -> &mut [u8] {
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const fn panic_at_const(_code: u32, _len: usize, _dst_len: usize) {
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// Note that we cannot format in constant expressions.
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panic!("encode_utf8: buffer does not have enough bytes to encode code point")
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}
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fn panic_at_rt(code: u32, len: usize, dst_len: usize) {
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panic!("encode_utf8: need {len} bytes to encode U+{code:04X} but buffer has just {dst_len}")
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}
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let len = len_utf8(code);
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match (len, &mut *dst) {
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(1, [a, ..]) => {
@@ -1782,8 +1790,7 @@ pub const fn encode_utf8_raw(code: u32, dst: &mut [u8]) -> &mut [u8] {
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*c = (code >> 6 & 0x3F) as u8 | TAG_CONT;
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*d = (code & 0x3F) as u8 | TAG_CONT;
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}
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// Note that we cannot format in constant expressions.
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_ => panic!("encode_utf8: buffer does not have enough bytes to encode code point"),
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_ => const_eval_select((code, len, dst.len()), panic_at_const, panic_at_rt),
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};
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// SAFETY: `<&mut [u8]>::as_mut_ptr` is guaranteed to return a valid pointer and `len` has been tested to be within bounds.
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unsafe { slice::from_raw_parts_mut(dst.as_mut_ptr(), len) }

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