Breaking changes to make for v2#

[1 ..] syntax#

Due to a bug in the parser we accept [1, ..] as a valid list value.

• Emits warning when used.
• Formatter rewrites it to desired syntax.

_ as a syntax#

This pattern doesn't make sense as one could write a instead. We don't want two ways of doing the same thing.

• Emits warning when used.
• Formatter rewrites it to desired syntax.

Shadowing imported values#

Do not allow shadowing an imported value, the same way one can't define two top level functions with the same name.

• Emits warning when used.

Import one module multiple times#

Do not allow one module to be imported multiple times. This is currently accepted so long as each import uses a different alias.

• Emits warning when used.

JavaScript runtime error fn property#

On JavaScript there is a deprecated fn property. This was a mistake, it should have been function. It still exists today due to backwards compatibility.

Do not allow guard with no condition#

It doesn't make sense to have an if guard followed by no condition, but the compiler allows this: case wibble { big if -> True }

• Emits warning when used.
• Formatter rewrites it to desired syntax.