8813: Get some more array lengths! r=lf- a=lf-
This is built on #8799 and thus contains its changes. I'll rebase it onto master when that one gets merged. It adds support for r-a understanding the length of:
* `let a: [u8; 2] = ...`
* `let a = b"aaa"`
* `let a = [0u8; 4]`
I have added support for getting the values of byte strings, which was not previously there. I am least confident in the correctness of this part and it probably needs some more tests, as we currently have only one test that exercised that part (!).
Fixes#2922.
Co-authored-by: Jade <software@lfcode.ca>
Fix#2922: add unknown length as a condition for a type having unknown.
Incorporate reviews:
* Extract some of the const evaluation workings into functions
* Add fixmes on the hacks
* Add tests for impls on specific array lengths (these work!!! 😁)
* Add tests for const generics (indeed we don't support it yet)
8799: Add basic support for array lengths in types r=flodiebold a=lf-
This recognizes `let a = [1u8, 2, 3]` as having type `[u8; 3]` instead
of the previous `[u8; _]`. Byte strings and `[0u8; 2]` kinds of range
array declarations are unsupported as before.
I don't know why a bunch of our rustc tests had single quotes inside
strings un-escaped by `UPDATE_EXPECT=1 cargo t`, but I don't think it's
bad? Maybe something in a nightly?
Co-authored-by: Jade <software@lfcode.ca>
This recognizes `let a = [1u8, 2, 3]` as having type `[u8; 3]` instead
of the previous `[u8; _]`. Byte strings and `[0u8; 2]` kinds of range
array declarations are unsupported as before.
I don't know why a bunch of our rustc tests had single quotes inside
strings un-escaped by `UPDATE_EXPECT=1 cargo t`, but I don't think it's
bad? Maybe something in a nightly?
I'd prefer getting rid of it, but it's used in the impl search and not
super easy to replace there (I think ideally the impl search would do
proper unification, but that's a bit more complicated).
Almost all uses actually only care about ADT substs, so it's better to
be explicit. The methods were a bad abstraction anyway since they
already didn't include the inner types of e.g. `TyKind::Ref` anymore.
8364: Memory usage improvements r=jonas-schievink a=alexmaco
These are mostly focused on splitting up enum variants with large size differences between variants by `Box`-ing things up.
In my testing this reduces the memory usage somewhere in the low percentages, even though the measurements are quite noisy.
Co-authored-by: Alexandru Macovei <alexnmaco@gmail.com>
Rationale: only a minority of variants used almost half the size.
By keeping large members (especially in Option) behind a box
the memory cost is only payed when the large variants are needed.
This reduces the size Vec<Expr> needs to allocate.
