Fixes#16311
The actual cause of #16311 is the `start_is_zero` special case:
```zig
const range_len = if (end_val == .none or start_is_zero)
end_val
else
try parent_gz.addPlNode(.sub, input, Zir.Inst.Bin{
.lhs = end_val,
.rhs = start_val,
});
```
It only happens if the range start is 0. In that case we would not perform any type checking.
Only in the other cases coincidentally `.sub` performs type checking in Sema, but the errors are still rather poor:
```
$ zig test x.zig
x.zig:9:15: error: invalid operands to binary expression: 'Pointer' and 'Pointer'
for ("abc".."def") |val| {
~~~~~^~~~~~~
```
Note how it's the same as if I use `-`:
```
x.zig:9:11: error: invalid operands to binary expression: 'Pointer' and 'Pointer'
"abc" - "def";
~~~~~~^~~~~~~
```
Now after this PR, the errors are much clearer for both range start and end:
```
x.zig:9:10: error: expected type 'usize', found '*const [3:0]u8'
for ("abc".."def") |val| {
^~~~~
```
This is why I decided to use `.ty` instead of `.coerced_ty` for both range start and end rather than
just perform type checking in that `end_val == .none or start_is_zero` case.
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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