michael@0: diff --git a/mfbt/double-conversion/utils.h b/mfbt/double-conversion/utils.h
michael@0: --- a/mfbt/double-conversion/utils.h
michael@0: +++ b/mfbt/double-conversion/utils.h
michael@0: @@ -275,19 +275,18 @@ class StringBuilder {
michael@0:  // There is an additional use for BitCast.
michael@0:  // Recent gccs will warn when they see casts that may result in breakage due to
michael@0:  // the type-based aliasing rule.  If you have checked that there is no breakage
michael@0:  // you can use BitCast to cast one pointer type to another.  This confuses gcc
michael@0:  // enough that it can no longer see that you have cast one pointer type to
michael@0:  // another thus avoiding the warning.
michael@0:  template <class Dest, class Source>
michael@0:  inline Dest BitCast(const Source& source) {
michael@0: -  // Compile time assertion: sizeof(Dest) == sizeof(Source)
michael@0: -  // A compile error here means your Dest and Source have different sizes.
michael@0: -  typedef char VerifySizesAreEqual[sizeof(Dest) == sizeof(Source) ? 1 : -1];
michael@0: +  static_assert(sizeof(Dest) == sizeof(Source),
michael@0: +                "BitCast's source and destination types must be the same size");
michael@0:  
michael@0:    Dest dest;
michael@0:    memmove(&dest, &source, sizeof(dest));
michael@0:    return dest;
michael@0:  }
michael@0:  
michael@0:  template <class Dest, class Source>
michael@0:  inline Dest BitCast(Source* source) {