Bug Report

When dict unpacking is used to dynamically add optional keys to a TypedDict,mypy raises atypeddict-item error.
As dict unpacking is used to fill some keys from the TypedDict, my understanding is thatmypy could validate the unpacked dictionaries considering all keys asNotRequired, and only the final TypedDict respecting its formal definition.

To Reproduce

Gist:https://mypy-play.net/?mypy=latest&python=3.13&gist=b3377281f7f5a6f83dd9962d60302827

fromtypingimportNotRequired,TypedDictclassProject(TypedDict):name:strversion:NotRequired[str]defbuild_project(name:str,version:str|None=None)->Project:return {"name":name,**({"version":version}ifversionisnotNoneelse {})    }

Actual Behavior

$ mypy .main.py:12: error: Missing key "name" for TypedDict "Project"  [typeddict-item]Found 1 error in 1 file (checked 1 source file)

Your Environment

• Mypy version used:1.17.0
• Mypy command-line flags: N/A
• Mypy configuration options frommypy.ini (and other config files): N/A
• Python version used:3.13.5