chore: compose inferring map dtypes using ibis.array()

ibis/expr/types/maps.py

@@ -13,7 +13,7 @@
 if TYPE_CHECKING:
     from collections.abc import Iterable, Mapping
 
-    from ibis.expr.types import dt
+    from ibis.expr import datatypes as dt
 
 
 @public
@@ -492,6 +492,8 @@ def map(
     │ {'b': 3.0}                                    │
     └───────────────────────────────────────────────┘
     """
+    from ibis.expr import datatypes as dt
+
     if keys is None:
         if type is None:
             raise TypeError("Must specify a type when keys is None")
@@ -502,8 +504,11 @@ def map(
     else:
         if values is None:
             keys, values = tuple(keys.keys()), tuple(keys.values())
-        if not isinstance(keys, Value) and len(keys) == 0 and type is None:
-            raise TypeError("Must specify a type when keys is empty")
+        type = dt.dtype(type) if type is not None else None
+        key_type = dt.Array(value_type=type.key_type) if type is not None else None
+        value_type = dt.Array(value_type=type.value_type) if type is not None else None
+        keys = ibis.array(keys, type=key_type)
+        values = ibis.array(values, type=value_type)
         result = ops.Map(keys, values).to_expr()
 
     if type is not None: