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  1. Swift
  2. SR-8354

Runtime warning on failure to demangle type

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    Details

    • Type: Bug
    • Status: Resolved
    • Priority: Medium
    • Resolution: Done
    • Component/s: Compiler
    • Labels:
    • Environment:

      Swift 4.2 (Xcode 10 beta 4)
      Swift 4.2-dev master branch (c2452cf)

      Description

      Running the following code will result in the output below.

      let l = (0...40).lazy.filter({ _ in true })
      Mirror(reflecting: l).children.forEach { print($0) }
      
      (label: Optional("_base"), value: ClosedRange(0...40))
      SWIFT RUNTIME BUG: unable to demangle type of field '_predicate'. mangled type name is 'Sb7ElementSTQzc'
      (label: Optional("_predicate"), value: ())
      

      This doesn't occur in Swift 4.1.2. The output there is:

      (label: Optional("_base"), value: CountableClosedRange(0...40))
      (label: Optional("_predicate"), value: (Function))
      

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              Assignee:
              Unassigned Unassigned
              Reporter:
              Christopher Christopher Rogers
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                Updated:
                Resolved: