xcode6 - Getting dyld_fatal_error after updating to Xcode 6 beta 4 using swift

Question

I just recently downloaded Xcode 6 beta 4, and my swift project compiles with no errors but before it gets to my code I get a dyld_fatal_error just above start in the call stack.

and a breakpoint in some assembly code with a nop instruction

The console error I get is

dyld: lazy symbol binding failed: Symbol not found: __TFSsa6C_ARGVGVSs13UnsafePointerGS_VSs4Int8__
  Referenced from: /Users/username/Library/Developer/Xcode/DerivedData/Sudoku-dhrdonaeqzsgcvewndimxbbsltnc/Build/Products/Debug/Sudoku.app/Contents/MacOS/Sudoku
  Expected in: /Users/username/Library/Developer/Xcode/DerivedData/Sudoku-dhrdonaeqzsgcvewndimxbbsltnc/Build/Products/Debug/Sudoku.app/Contents/MacOS/../Frameworks/libswift_stdlib_core.dylib

dyld: Symbol not found: __TFSsa6C_ARGVGVSs13UnsafePointerGS_VSs4Int8__
  Referenced from: /Users/username/Library/Developer/Xcode/DerivedData/Sudoku-dhrdonaeqzsgcvewndimxbbsltnc/Build/Products/Debug/Sudoku.app/Contents/MacOS/Sudoku
  Expected in: /Users/username/Library/Developer/Xcode/DerivedData/Sudoku-dhrdonaeqzsgcvewndimxbbsltnc/Build/Products/Debug/Sudoku.app/Contents/MacOS/../Frameworks/libswift_stdlib_core.dylib

Just so you know the project still compiles, and runs fine with Xcode 6 beta 3.

question from:https://stackoverflow.com/questions/24878274/getting-dyld-fatal-error-after-updating-to-xcode-6-beta-4-using-swift

Answer 1

Most extremely weird problems like this can be solved with a Clean & Build (or perhaps relaunch Xcode). You might also consider deleting the relevant folders from ~/Library/Developer/Xcode/DerivedData.