take advantage of ::None for identifying unreachable code

base/error.jl

@@ -9,8 +9,8 @@ macro unexpected()
  :(error("unexpected branch reached"))
 end
 
-rethrow() = ccall(:jl_rethrow, Void, ())
-rethrow(e) = ccall(:jl_rethrow_other, Void, (Any,), e)
+rethrow() = ccall(:jl_rethrow, Void, ())::None
+rethrow(e) = ccall(:jl_rethrow_other, Void, (Any,), e)::None
 backtrace() = ccall(:jl_get_backtrace, Array{Any,1}, ())
 
 ## system error handling ##

base/exports.jl

@@ -17,7 +17,7 @@ export
  Operators,
  Errno,
  Meta,
- 
+
 # Types
  AbstractMatrix,
  AbstractSparseMatrix,

base/sysimg.jl

@@ -253,7 +253,7 @@ precompile(eval_user_input, (Expr, Bool))
 precompile(print, (Float64,))
 precompile(a2t, (Array{Any,1},))
 precompile(flush, (IOStream,))
-precompile(getindex, (Type{ByteString}, ASCIIString, ASCIIString, ASCIIString, ASCIIString, ASCIIString, ASCIIString))
+precompile(getindex, (Type{ByteString}, ASCIIString, ASCIIString, ASCIIString))
 precompile(int, (Int,))
 precompile(uint, (Uint,))
 precompile(_atexit, ())
@@ -295,6 +295,13 @@ precompile(abstract_eval_arg, (Uint8, ObjectIdDict, StaticVarInfo))
 precompile(occurs_outside_tupleref, (Function, Symbol, StaticVarInfo, Int))
 precompile(search, (ASCIIString, Regex, Int))
 precompile(setindex!, (Vector{Uint8}, Uint8, Int))
+precompile(first, (Range1{Int},))
+precompile(last, (Range1{Int},))
+precompile(isempty, (ASCIIString,))
+precompile(normpath, (ASCIIString,))
+precompile(print, (ASCIIString,))
+precompile(println, (TTY,))
+precompile(print, (TTY,Char))
 
 # invoke type inference, running the existing inference code on the new
 # inference code to cache an optimized version of it.

src/cgutils.cpp

@@ -532,7 +532,7 @@ static jl_value_t *expr_type(jl_value_t *e, jl_codectx_t *ctx)
  return (jl_value_t*)jl_any_type;
  }
 type_of_constant:
- if (jl_is_datatype(e))
+ if (jl_is_datatype(e) || jl_is_uniontype(e))
  return (jl_value_t*)jl_wrap_Type(e);
  return (jl_value_t*)jl_typeof(e);
 }

src/codegen.cpp

@@ -1045,7 +1045,17 @@ static Value *emit_known_call(jl_value_t *ff, jl_value_t **args, size_t nargs,
  jl_value_t *tp0 = jl_tparam0(ty);
  if (jl_subtype(arg, tp0, 0)) {
  JL_GC_POP();
- return emit_expr(args[1], ctx);
+ Value *v = emit_expr(args[1], ctx);
+ if (tp0 == jl_bottom_type) {
+ return builder.CreateUnreachable();
+ }
+ return v;
+ }
+ if (tp0 == jl_bottom_type) {
+ emit_expr(args[1], ctx);
+ emit_error("reached code declared unreachable", ctx);
+ JL_GC_POP();
+ return builder.CreateUnreachable();
  }
  if (!jl_is_tuple(tp0) && jl_is_leaf_type(tp0)) {
  Value *arg1 = emit_expr(args[1], ctx);