Same here: Xcode 26 crashes as soon as Coding Intelligence is enabled or Coding Intelligence tab is opened. Crashes for this particular one project only.
Deleting xcuserdata did not help.
Can't seem to find where Xcode is storing Coding Intelligence chat history, which seems to be the culprit.
Crash report excerpt:
"exception" : {"codes":"0x0000000000000001, 0x000000016010bfb0","rawCodes":[1,5906677680],"type":"EXC_BREAKPOINT","signal":"SIGTRAP"},
"termination" : {"flags":0,"code":5,"namespace":"SIGNAL","indicator":"Trace\/BPT trap: 5","byProc":"exc handler","byPid":2620},
"os_fault" : {"process":"Xcode"},
"extMods" : {"caller":{"thread_create":0,"thread_set_state":0,"task_for_pid":0},"system":{"thread_create":0,"thread_set_state":0,"task_for_pid":0},"targeted":{"thread_create":0,"thread_set_state":0,"task_for_pid":0},"warnings":0},
"faultingThread" : 0,
"threads" : [{"frames":[{"imageOffset":5242800,"symbol":"closure #1 in SourceEditorDataSource.ideChat_gracefullyApplyChangesToReflect(_:editApplier:)","symbolLocation":2292,"imageIndex":339},{"imageOffset":3689220,"symbol":"SourceEditorDataSource.performEditTransaction(_:)","symbolLocation":52,"imageIndex":129},{"imageOffset":5237704,"symbol":"SourceEditorDataSource.ideChat_gracefullyApplyChangesToReflect(_:editApplier:)","symbolLocation":1168,"imageIndex":339},{"imageOffset":5207920,"symbol":"ChatInputEditorView.updateView(_:context:)","symbolLocation":624,"imageIndex":339},