[ty] dataclasses.field support

crates/ty_python_semantic/resources/mdtest/dataclasses/fields.md

@@ -0,0 +1,35 @@
+# Dataclass fields
+
+## Basic
+
+```py
+from dataclasses import dataclass, field
+
+@dataclass
+class Member:
+    name: str
+    role: str = field(default="user")
+    tag: str | None = field(default=None, init=False)
+
+# TODO: this should not include the `tag` parameter, since it has `init=False` set
+# revealed: (self: Member, name: str, role: str = Unknown, tag: str | None = Unknown) -> None
+reveal_type(Member.__init__)
+
+alice = Member(name="Alice", role="admin")
+reveal_type(alice.role)  # revealed: str
+alice.role = "moderator"
+
+# TODO: this should be an error, `tag` has `init=False`
+bob = Member(name="Bob", tag="VIP")
+```
+
+## The `field` function
+
+```py
+from dataclasses import field
+
+# TODO: this should be `Literal[1]`. This is currently blocked on enum support, because
+# the `dataclasses.field` overloads make use of a `_MISSING_TYPE` enum, for which we
+# infer a @Todo type, and therefore pick the wrong overload.
+reveal_type(field(default=1))  # revealed: Unknown
+```