"Why move the compiler to Go?

  Not for validation; we have more pragmatic motives:
  Go is easier to write (correctly) than C.
  Go is easier to debug than C (even absent a debugger).
  Go is the only language you'd need to know; encourages contributions.
  Go has better modularity, tooling, testing, profiling, ...
  Go makes parallel execution trivial.
  Already seeing benefits, and it's early yet.
  Design document: golang.org/s/go13compiler"

  "Why translate it, not write it from scratch? 
  Correctness, testing.
  Steps:
  Write a custom translator from C to Go.
  Run the translator, iterate until success.
  Measure success by bit-identical output.
  Clean up the code by hand and by machine.
  Turn it from C-in-Go to idiomatic Go (still happening)."