This is a bit harder than it seems at first glance. Actually resolving
the type is the easy part: the interesting thing is actually getting the
capture value. We split this into three cases:
* If all payload types are the same (as is required in status quo), we
can just do what we already do: get the first field value.
* If all payloads are in-memory coercible to the resolved type, we still
fetch the first field, but we also emit a `bitcast` to convert to the
resolved type.
* Otherwise, we need to handle each case separately. We emit a nested
`switch_br` which, for each possible case, gets the corresponding
union field, and coerces it to the resolved type. As an optimization,
the inner switch's 'else' prong is used for any peer which is
in-memory coercible to the target type, and the bitcast approach
described above is used.
Pointer captures have the additional constraint that all payload types
must be in-memory coercible to the resolved type.
Resolves: #2812
This will do zig run on the code and expect exit code 0.
// run
Incremental Compilation
Make multiple files that have ".", and then an integer, before the ".zig"
extension, like this:
hello.0.zig
hello.1.zig
hello.2.zig
Each file can be a different kind of test, such as expecting compile errors,
or expecting to be run and exit(0). The test harness will use these to simulate
incremental compilation.
At the time of writing there is no way to specify multiple files being changed
as part of an update.
Subdirectories
Subdirectories do not have any semantic meaning but they can be used for
organization since the test harness will recurse into them. The full directory
path will be prepended as a prefix on the test case name.
Limiting which Backends and Targets are Tested
// run
// backend=stage2,llvm
// target=x86_64-linux,x86_64-macos
Possible backends are:
stage1: equivalent to -fstage1.
stage2: equivalent to passing -fno-stage1 -fno-LLVM.
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