cast_possible_truncation: Support size_of, align_of, and size_of_val
#15488
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Lintcheck changes for c5a67a8
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☔ The latest upstream changes (possibly e9b7045) made this pull request unmergeable. Please resolve the merge conflicts. |
blyxyas
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Sep 5, 2025
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| ExprKind::Call(callee, [_]) => match self.get_fn_diagnostic_name(callee) { | ||
| // `align_of_val` doesn't have a diagnostic name, unfortunately. | ||
| // Some(sym::mem_align_of_val) => self.align_of_call(callee), | ||
| Some(sym::mem_size_of_val) => self.size_of_call(callee), | ||
| _ => None, |
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Suggested change
| ExprKind::Call(callee, [_]) => match self.get_fn_diagnostic_name(callee) { | |
| // `align_of_val` doesn't have a diagnostic name, unfortunately. | |
| // Some(sym::mem_align_of_val) => self.align_of_call(callee), | |
| Some(sym::mem_size_of_val) => self.size_of_call(callee), | |
| _ => None, |
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| ExprKind::Call(callee, []) => match self.get_fn_diagnostic_name(callee) { | ||
| Some(sym::i8_legacy_fn_max_value) => Some(Constant::Int(i8::MAX as u128)), | ||
| Some(sym::i16_legacy_fn_max_value) => Some(Constant::Int(i16::MAX as u128)), | ||
| Some(sym::i32_legacy_fn_max_value) => Some(Constant::Int(i32::MAX as u128)), | ||
| Some(sym::i64_legacy_fn_max_value) => Some(Constant::Int(i64::MAX as u128)), | ||
| Some(sym::i128_legacy_fn_max_value) => Some(Constant::Int(i128::MAX as u128)), | ||
| Some(sym::mem_align_of) => self.align_of_call(callee), | ||
| Some(sym::mem_size_of) => self.size_of_call(callee), | ||
| _ => None, | ||
| }, |
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[..] The rest pattern also allows for zero-sized arrays, no need for the extra branch.
Suggested change
| ExprKind::Call(callee, []) => match self.get_fn_diagnostic_name(callee) { | |
| Some(sym::i8_legacy_fn_max_value) => Some(Constant::Int(i8::MAX as u128)), | |
| Some(sym::i16_legacy_fn_max_value) => Some(Constant::Int(i16::MAX as u128)), | |
| Some(sym::i32_legacy_fn_max_value) => Some(Constant::Int(i32::MAX as u128)), | |
| Some(sym::i64_legacy_fn_max_value) => Some(Constant::Int(i64::MAX as u128)), | |
| Some(sym::i128_legacy_fn_max_value) => Some(Constant::Int(i128::MAX as u128)), | |
| Some(sym::mem_align_of) => self.align_of_call(callee), | |
| Some(sym::mem_size_of) => self.size_of_call(callee), | |
| _ => None, | |
| }, | |
| ExprKind::Call(callee, [..]) => match self.get_fn_diagnostic_name(callee) { | |
| Some(sym::i8_legacy_fn_max_value) => Some(Constant::Int(i8::MAX as u128)), | |
| Some(sym::i16_legacy_fn_max_value) => Some(Constant::Int(i16::MAX as u128)), | |
| Some(sym::i32_legacy_fn_max_value) => Some(Constant::Int(i32::MAX as u128)), | |
| Some(sym::i64_legacy_fn_max_value) => Some(Constant::Int(i64::MAX as u128)), | |
| Some(sym::i128_legacy_fn_max_value) => Some(Constant::Int(i128::MAX as u128)), | |
| Some(sym::mem_align_of) => self.align_of_call(callee), | |
| Some(sym::mem_size_of) | Some(sym::mem_size_of_val)=> self.size_of_call(callee), | |
| _ => None, | |
| }, |
| } | ||
| } | ||
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| fn align_of_call(&self, callee: &Expr<'_>) -> Option<Constant<'tcx>> { |
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Could you add some documentation here for these two functions?
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ping @RunDevelopment 🏓 I'm not sure if you saw my review or if it just flew under the radar? |
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fixes parts of #9613, related to #12962
Unlike #12962, I added support for
size_of,align_of, andsize_of_valtoConstEval, so all lints using it benefit from this change.cast_possible_truncationitself changed relatively little. Functions calls are now delegated to const eval and ptr-sized to fixed-sized casts now considerfrom_nbits.changelog: [
cast_possible_truncation]: supportsize_of,align_of, andsize_of_valMy intention with this PR is not to superceed #12962, but to get in a simple improvement while I work on #15342.