`castTruncatedData` was a poorly worded error (all shrinking casts
"truncate bits", it's just that we assume those bits to be zext/sext of
the other bits!), and `negativeToUnsigned` was a pointless distinction
which forced the compiler to emit worse code (since two separate safety
checks were required for casting e.g. 'i32' to 'u16') and wasn't even
implemented correctly. This commit combines those safety panics into one
function, `integerOutOfBounds`. The name maybe isn't perfect, but that's
not hugely important; what matters is the new default message, which is
clearer than the old ones: "integer does not fit in destination type".
This is all of the expected 0.14.0 progress on #21530, which can now be
postponed once this commit is merged.
This required rewriting the (un)wrap operations since the original
implementations were extremely buggy.
Also adds an easy way to retrigger Sema OPV bugs so that I don't have to
keep updating #22419 all the time.
Most of this migration was performed automatically with `zig fmt`. There
were a few exceptions which I had to manually fix:
* `@alignCast` and `@addrSpaceCast` cannot be automatically rewritten
* `@truncate`'s fixup is incorrect for vectors
* Test cases are not formatted, and their error locations change
This matches master branch. We can look into adding more target coverage
as we switch to stage2. As it stands, this works around having to
duplicate the "Executor" logic to figure out when to not run the tests
due to them being non-native.
* migrate runtime safety tests to the new test harness
- this required adding compare output / execution support for stage1
to the test harness.
* rename `zig build test-stage2` to `zig build test-cases` since it now
does quite a bit of stage1 testing actually. I named it this way
since the main directory in the source tree associated with these
tests is "test/cases/".
* add some documentation for the test manifest format.
