A when branch matching on multiple record patterns using field punning within tags causes duplicate name error

[isaacvando]

# This works as expected
func1 = \val ->
    when val is
        A x | B x -> x
        C -> {}

# This works as expected
func2 = \val ->
    when val is
        A { x } | B x -> x
        C -> {}

# This works as expected
func3 = \val ->
    when val is
        A { x: x } | B { x: x } -> x
        C -> {}

# This causes a duplicate name error
func4 = \val ->
    when val is
        A { x } | B { x } -> x
        C -> {}

── DUPLICATE NAME in Model.roc ─────────────────────────────────────────────────

The x name is first defined here:

151│          A { x } | B { x } -> x
                ^^^^^

But then it's defined a second time here:

151│          A { x } | B { x } -> x
                          ^^^^^

Since these variables have the same name, it's easy to use the wrong
one by accident. Give one of them a new name.


── NAME NOT BOUND IN ALL PATTERNS in Model.roc ─────────────────────────────────

x is not bound in all patterns of this when branch

151│          A { x } | B { x } -> x
                  ^

Identifiers introduced in a when branch must be bound in all patterns
of the branch. Otherwise, the program would crash when it tries to use
an identifier that wasn't bound!

────────────────────────────────────────────────────────────────────────────────

2 errors and 0 warnings found in 15 ms