Allow blocks in const expressions #14183
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| StmtExpr(ref expr, _) => block_span_err(expr.span), | ||
| StmtSemi(ref semi, _) => block_span_err(semi.span), | ||
| StmtMac(..) => v.tcx.sess.span_bug(e.span, | ||
| "unexpanded statement macro in const?!") |
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I think macro_rules! macros may stick around un-expanded. Can you add a test case too make sure we don't ICE here?
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Do you mean macro_rules! itself, or macros generated by it? For the latter there is a testcase already.
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Added a testcase, doesn't seem to ICE. :)
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Or actually, can you add another test with the macro tagged with #[macro_export]? Those seem to be the ones that stick around.
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static BLOCK_MACRO_RULES_EXPORTED: uint = {
#[macro_export]
macro_rules! baz {
() => (612)
}
baz!()
};
gives me the error
/home/marvin/dev/rust/fork/rust/src/test/run-pass/const-block-item.rs:51:19: 51:20 error: expected item after attributes
/home/marvin/dev/rust/fork/rust/src/test/run-pass/const-block-item.rs:51 #[macro_export]
^
Am I doing something wrong?
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Oh cool, looks like the parser doesn't even accept that currently (it wouldn't make much sense anyway I think). Thanks for checking!
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I get the same error in a regular function as well:
pub fn main() {
#[macro_export]
macro_rules! baz {
() => (612)
}
}
Only blocks with tail expressions that are const expressions and items are allowed.
bors
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May 14, 2014
Closes #14184 (std: Move the owned module from core to std) Closes #14183 (Allow blocks in const expressions) Closes #14176 (Add tests for from_bits.) Closes #14175 (Replaced ~T by Box<T> in manual) Closes #14173 (Implements Default trait for BigInt and BigUint) Closes #14171 (Fix #8391) Closes #14159 (Clean up unicode code in libstd) Closes #14126 (docs: Add a not found page) Closes #14123 (add a line to the example to clarify semantics) Closes #14106 (Pretty printer improvements) Closes #14083 (rustllvm: Add LLVMRustArrayType) Closes #13957 (io: Implement process wait timeouts)
lilyball
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May 18, 2014
Change `bytes!()` to return
{
static BYTES: &'static [u8] = &[...];
BYTES
}
This gives it the `'static` lifetime, whereas before it had an rvalue
lifetime. Until recently this would have prevented assigning `bytes!()`
to a static, as in
static FOO: &'static [u8] = bytes!(1,2,3);
but rust-lang#14183 fixed it so blocks are now allowed in constant expressions
(with restrictions).
Fixes rust-lang#11641.
bors
added a commit
that referenced
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May 18, 2014
Change `bytes!()` to return
{
static BYTES: &'static [u8] = &[...];
BYTES
}
This gives it the `'static` lifetime, whereas before it had an rvalue
lifetime. Until recently this would have prevented assigning `bytes!()`
to a static, as in
static FOO: &'static [u8] = bytes!(1,2,3);
but #14183 fixed it so blocks are now allowed in constant expressions
(with restrictions).
Fixes #11641.
This was referenced May 21, 2014
lnicola
pushed a commit
to lnicola/rust
that referenced
this pull request
Mar 13, 2023
minor: Try to improve the `rustfmt.overrideCommand` docs Closes rust-lang#14078
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Only blocks with tail expressions that are const expressions
and items are allowed.
Implements rust-lang/rfcs#71 (#14181)