There's arguably no use case ever for that in the context of on-chain
Plutus. Strings are really just meant to be used for tracing. They
aren't meant to be manipulated as heavily as in classic programming
languages.
Before that commit, the type-checker would allow unsafe list patterns
such as:
```
let [x] = xs
when xs is {
[x] -> ...
[x, ..] -> ...
}
```
This is quite unsafe and can lead to confusing situations. Now at
least the compiler warns about this. It isn't perfect though,
especially in the presence of clause guards. But that's a start.
Whoopsie... || and && were treated with the same precedence, causing very surprising behavior down the line.
I noticed this because of the auto-formatter adding parenthesis where it really shouldn't. The problem came actually from the parser and how it constructed the AST.
fix conversion from inner opaque type for when and assignment
This fixes Clause being used in cases where ListClause or TupleClause should be used
Reset defined and zero arg functions between each code gen
Fixes for optimizations when encountering shadowed variables
* fix assert on pattern Var
* fix tuple index unwrapping closes#334
* allow wrapping when casting with let
* allow wrapping when casting via function call
I decided to invert how I'm doing it. I'm passing
in a new argument to unify in environment called
allow_cast: bool and essentially at various
unification sites I can control whether or not I
want to allow casting to even occur. So we can
assume it's false by default always and then we
turn it on in a few places vs. just opening the
flood gates and locking it down at various sites
as they come up# Please enter the commit message
for your changes. Lines starting
* you cannot cast FROM Data with a `let`
* you cannot cast FROM Data by passing
Data to none Data when calling a function
* you MUST use `assert` to cast from data
* you can cast INTO Data with a `let`
* you can cast INTO Data by passing none Data
to Data when calling a function
* You cannot assert cast Data without an
annotation
Kasey White