Typed Dictionaries can allow different typed keys/values when using operator[]

[aaronp64]

Tested versions

Latest master v4.4.dev.custom_build [2124995]

System information

Windows 10

Issue description

Adding to a typed dictionary using operator[] allows adding keys/values of different types, if the types aren't known until run time, or if the typed dictionary is passed into a function that takes an untyped dictionary. In both cases, using get_or_add catches the difference and gives an error.

Steps to reproduce

Create a new project, and add code below to main scene:

func _ready():
	var dictionary : Dictionary[Node, Node] = { }
	# dictionary["test1"] = 1 # Gives error in editor
	# dictionary.get_or_add(get_key(), get_value()) # Type check error
	dictionary[get_key()] = get_value()
	_test_dictionary_func(dictionary)
	print(dictionary)

func _test_dictionary_func(d : Dictionary):
	# d.get_or_add("test2", 2) # Type check error
	d["test2"] = 2

func get_key():
	return "test1"

func get_value():
	return 1

This prints { "test1": 1, "test2": 2 } without giving any errors

Minimal reproduction project (MRP)

N/A

[SBNovaScript]

As GDScript is a gradually typed language, is there a need to implement this type inference? Would we expect this dictionary's type to not be cast to the untyped dictionary? As get_or_add verifies types during runtime, it might make more sense to prefer that when potentially using mixed types. I'm all for increased type inference accuracy though.

[dalexeev]

CC @Repiteo

[Repiteo]

Oh shoot, good catch! This was an erroneous regression in one of the rebases of the typed dictionary PR. Making a fix and putting up a testcase to make sure this won't happen again 👍