Fix bitshift operators on Bool

Previously triggered a stack overflow due to recursive definition.

Author: nalimilan

base/bool.jl

@@ -20,6 +20,10 @@ typemax(::Type{Bool}) = true
 (|)(x::Bool, y::Bool) = box(Bool,or_int(unbox(Bool,x),unbox(Bool,y)))
 ($)(x::Bool, y::Bool) = (x!=y)
 
+>>(x::Bool, c::Unsigned) = Int(x) >> c
+<<(x::Bool, c::Unsigned) = Int(x) << c
+>>>(x::Bool, c::Unsigned) = Int(x) >>> c
+
 signbit(x::Bool) = false
 sign(x::Bool) = x
 abs(x::Bool) = x

test/int.jl

@@ -190,3 +190,8 @@ end
 
 # issue #16700
 @test_throws MethodError 1.0 >> 8
+
+# PR #16988
+@test true << 2 === 1 << 2
+@test true >> 2 === 1 >> 2
+@test true >>> 2 === 1 >>> 2