Named tuples type inference broken

[plajjan]

Acton Version

0.22.0.20240426.8.47.57

Steps to Reproduce and Observed Behavior

actor main(env):
    # Items in a tuple can be of different types
    t = ("foo", 42)
    # Fields are accessed by their index and using field / attribute selection style:
    print(t)
    print(t.0)
    print(t.1)
    
    # Tuples can use named fields
    nt = (a="bar", b=1337)
    print(nt)
    print(nt.a)
    print(nt.b)

    env.exit(0) 

actonc fails to infer the type of the named tuple nt, like so:

Building project in /home/user/foo
  Compiling example.act for release

ERROR: Error when compiling example module: Type error

Cannot satisfy the following simultaneous constraints for the unknown types t0, t1:

   |
15 |    print(nt.b)
   |          ^^
The type of the indicated expression (which we call t0) must have an attribute b with type _; no such type is known.

   |
14 |    print(nt.a)
   |          ^^
The type of the indicated expression (which we call t0) must have an attribute a with type _; no such type is known.

   |
12 |    nt = (a="bar", b=1337)
   |                     ^^^^
The type of the indicated expression (which we call t1) must implement __builtin__.Number

   |
12 |    nt = (a="bar", b=1337)
   |         ^^^^^^^^^^^^^^^^^
The type of the indicated expression (inferred to be (a: __builtin__.str, b: t1)) must be a subclass of t0

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 

actonc exited with code:  1  terminated with signal: 0

adding an explicit type signature fixes it.

Expected Behavior

Success