While the discussion about how to refactor test framework is not
finished (#1654), make this change: move `rm -rf build` in the
beginning of the test. For these reasons:
* it is useful to inspect the contents of the `build` directory
especially after the test failure
* if build crashes mid-test (e.g. process killed), next run should
not be affected by the `build` directory from the previous run
This adds new `Int8`, `Int16`, `Int32` and `Int64` data types
to the compiler, thus working towards properly specified integer
types as discussed in #1048.
In addition, the following changes / corrections are made:
* Support casts from `Char`, `String`, and `Double` to all integer
types (and back). This fixes#1270.
* Make sure that all casts to limited-precision integers are properly
bounds checked (this was not the case so far for casts from `String`
and `Double` to `Int`)
* Add a thorough set of tests to make sure all bounds checks work
correctly for all supported casts and arithmetic operations
