Emit error when range pattern is empty #2795
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Fixes Rust-GCC#2794 gcc/rust/ChangeLog: * checks/errors/rust-ast-validation.cc (ASTValidation::visit): Check values of lower and upper bounds and emit E0030 if needed. * checks/errors/rust-ast-validation.h: Add function declaration for validation of `AST::RangePattern`. * parse/rust-parse-impl.h (Parser::parse_literal_or_range_pattern): Added missed parameter. gcc/testsuite/ChangeLog: * rust/compile/issue-2794.rs: New test. Signed-off-by: Kushal Pal <[email protected]>
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I'm unsure this should be done at this stage of the compiler, this surely is simpler after a bit of desugaring. Have you taken a look at rustc's way of doing this ? Is it doing it this early ? |
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https://godbolt.org/z/sThP53WbG pub fn main() {
let _a = 1..=0;
match 0 {
1..=0 => {},
_ => {}
}
let (1..=0, _b) = (1, 0);
}It looks like the error only happens in match-like statements (the first line of the main function does not produce an error with rustc 1.49) |
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I wonder if that is the intended behaviour. I will ask in rustc if this is what they want or a missed case. |
you are right, rustc actually handles this error in typed-hir stage. |
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@braw-lee do you want some help on moving this to the typechecking phase? |
I couldn't find a cleaner way to get values of upper and lower bound. Tell me if there is a better way to get those values.
@CohenArthur @P-E-P