@@ -35,7 +35,7 @@ The kernel code supports a subset of the *Python 3.5* language. This section hig
1. Opening multiple contexts with a single `with` statement can result in incorrect behavior (see [this issue](https://github.com/m-labs/artiq/issues/1478)). As a workaround we recommend to open every context in a separate `with` statement.
1.`try`/`except`/`else`/`finally` clauses can cause "variable is not initialized" compile errors when a variable initialized in `try` is used later, even when the `except` clause re-raises the exception. This is due to limited liveness analysis. The problem is known and documented in [this issue](https://github.com/m-labs/artiq/issues/331), but will not be fixed. As a workaround we recommend to initialize the variable before the `try` clause.
1. ~~When explicitly or implicitly declaring a list/tuple/range variable inside a `try`/`with` statement which initializes to the return value of a function, the compiler crashes with an internal type error related to the IR. See [this DAX issue](https://gitlab.com/duke-artiq/dax/-/issues/43) and [this ARTIQ issue](https://github.com/m-labs/artiq/issues/1506). So far we found two workarounds for this bug: **a)** Declare and assign the (implicit) variable before the `try`/`with` statement, **b)** put the body of the `try`/`with` statement in a separate function and call that function.~~
1. Functions returning tuples have limited support for returning mixed types. It seems that integer types (i.e. `TInt32` and `TInt64`) combine in a return tuple without problems, but `TBool`, `TFloat`, and `TStr` can not be combined with any other types in a return tuple. Doing so results in a compiler bug `ValueError: location and highlights must refer to the same source buffer`. See [this issue](https://github.com/m-labs/artiq/issues/1671).
1. Functions returning tuples have limited support for returning mixed types. It seems that integer types (i.e. `TInt32` and `TInt64`) combine in a *return tuple* without problems, but `TBool`, `TFloat`, and `TStr` can not be combined with *any other types in a return tuple*. Doing so results in a compiler bug `ValueError: location and highlights must refer to the same source buffer`. See [this issue](https://github.com/m-labs/artiq/issues/1671). The easiest workaround seems to be to not type the return tuple.
1. Passing very "large" arguments to kernel functions (i.e. very large lists) can cause an LLVM IR parsing error: `RuntimeError: LLVM IR parsing error <string>:15604:29: error: value for 'column' too large, limit is 65535`. One way to mitigate this issue is to "pass" the variable as a kernel-invariant attribute instead.
