Xcode 8 very slow Swift compiling

Question

Ever since Swift 3 and Xcode 8 my project compiles quite slowly. Every time I add so much as an empty line to a file, recompiling takes a full minute. When I check the outpu

Answer 1

Make sure you're not combining arrays like let combinedArrays = array1 + array2. There's a known bug as well for type inference here, where Swift wastes time trying to figure out what type the combinedArrays should be. Instead, [array1, array2].joined() should work just as well, and compile far faster.