There's an unfortunate footgun in the current design of error sets.
The debug info type for every error set is the same as the debug info
type of the global error set, which is essentially an enum forward
declaration. The problem is that when we "replace" the forward
declaration with the final value, once we know all the possible errors,
we have to update the pointers of every error set.
So the footgun is that if you ever copy the debug info type of the
global error set, you have to add the address of the pointer to a list
of pointers that need to be updated once we "replace" the forward
declaration. I activated the footgun when I introduced the optimization
that `?anyerror` types are the same size as `anyerror` types (using 0 as
the null value), because I introduced a pointer copy of the global error
set debug info type, but forgot to add it to the list.
I'm sure that there is a better way to code this, which does not have
the footgun, but this commit contains only a fix, not a reworking of the
logic.
closes#1937
Previously, std.debug.assert would `@panic` in test builds,
if the assertion failed. Now, it's always `unreachable`.
This makes release mode test builds more accurately test
the actual code that will be run.
However this requires tests to call `std.testing.expect`
rather than `std.debug.assert` to make sure output is correct.
Here is the explanation of when to use either one, copied from
the assert doc comments:
Inside a test block, it is best to use the `std.testing` module
rather than assert, because assert may not detect a test failure
in ReleaseFast and ReleaseSafe mode. Outside of a test block, assert
is the correct function to use.
closes#1304
This commit contains everything from the copy-elision-2
branch that does not have to do with copy elision directly,
but is generally useful for master branch.
* All const values know their parents, when applicable, not
just structs and unions.
* Null pointers in const values are represented explicitly,
rather than as a HardCodedAddr value of 0.
* Rename "maybe" to "optional" in various code locations.
* Separate DeclVarSrc and DeclVarGen
* Separate PtrCastSrc and PtrCastGen
* Separate CmpxchgSrc and CmpxchgGen
* Represent optional error set as an integer, using the 0 value.
In a const value, it uses nullptr.
* Introduce type_has_one_possible_value and use it where applicable.
* Fix debug builds not setting memory to 0xaa when storing
undefined.
* Separate the type of a variable from the const value of a variable.
* Use copy_const_val where appropriate.
* Rearrange structs to pack data more efficiently.
* Move test/cases/* to test/behavior/*
* Use `std.debug.assertOrPanic` in behavior tests instead of
`std.debug.assert`.
* Fix outdated slice syntax in docs.
