fix 9765 test

Author: jrevels

base/compiler/tfuncs.jl

@@ -389,10 +389,17 @@ add_tfunc(typeassert, 2, 2,
           end, 4)
 add_tfunc(isa, 2, 2,
           function (@nospecialize(v), @nospecialize(t))
+              _t = t
               t, isexact = instanceof_tfunc(t)
               if !has_free_typevars(t)
                   if t === Bottom
-                      return Const(false)
+                      # we make this check because `t` could be `Bottom` when `_t` is e.g.
+                      # `Type{Union{}}`, in which case we want to return `Const(false)`
+                      if typeintersect(_t, Type) === Bottom && _t !== typeof(Bottom)
+                          return Bottom
+                      else
+                          return Const(false)
+                      end
                   elseif v ⊑ t
                       if isexact && isnotbrokensubtype(v, t)
                           return Const(true)

test/compiler/compiler.jl

@@ -1179,17 +1179,17 @@ let isa_tfunc = Core.Compiler.T_FFUNC_VAL[
     @test isa_tfunc(Array{Real}, Type{AbstractArray{Int}}) === Const(false)
     @test isa_tfunc(Array{Real, 2}, Const(AbstractArray{Real, 2})) === Const(true)
     @test isa_tfunc(Array{Real, 2}, Const(AbstractArray{Int, 2})) === Const(false)
-    @test isa_tfunc(DataType, Int) === Const(false)
+    @test isa_tfunc(DataType, Int) === Union{}
     @test isa_tfunc(DataType, Const(Type{Int})) === Bool
     @test isa_tfunc(DataType, Const(Type{Array})) === Bool
     @test isa_tfunc(UnionAll, Const(Type{Int})) === Bool # could be improved
     @test isa_tfunc(UnionAll, Const(Type{Array})) === Bool
     @test isa_tfunc(Union, Const(Union{Float32, Float64})) === Bool
     @test isa_tfunc(Union, Type{Union}) === Const(true)
     @test isa_tfunc(typeof(Union{}), Const(Int)) === Const(false) # any result is ok
-    @test isa_tfunc(typeof(Union{}), Const(Union{})) === Const(false)
+    @test isa_tfunc(typeof(Union{}), Const(Union{})) === Union{}
     @test isa_tfunc(typeof(Union{}), typeof(Union{})) === Const(false)
-    @test isa_tfunc(typeof(Union{}), Union{}) === Const(false) # any result is ok
+    @test isa_tfunc(typeof(Union{}), Union{}) === Union{} # any result is ok
     @test isa_tfunc(typeof(Union{}), Type{typeof(Union{})}) === Const(true)
     @test isa_tfunc(typeof(Union{}), Const(typeof(Union{}))) === Const(true)
     let c = Conditional(Core.SlotNumber(0), Const(Union{}), Const(Union{}))
@@ -1204,7 +1204,7 @@ let isa_tfunc = Core.Compiler.T_FFUNC_VAL[
     @test isa_tfunc(Val{1}, Type{Val{T}} where T) === Bool
     @test isa_tfunc(Val{1}, DataType) === Bool
     @test isa_tfunc(Any, Const(Any)) === Const(true)
-    @test isa_tfunc(Any, Union{}) === Const(false) # any result is ok
+    @test isa_tfunc(Any, Union{}) === Union{} # any result is ok
     @test isa_tfunc(Any, Type{Union{}}) === Const(false)
     @test isa_tfunc(Union{Int64, Float64}, Type{Real}) === Const(true)
     @test isa_tfunc(Union{Int64, Float64}, Type{Integer}) === Bool