diff --git a/base/compiler/typelimits.jl b/base/compiler/typelimits.jl
index 3de2627f425695..788063c302bafb 100644
--- a/base/compiler/typelimits.jl
+++ b/base/compiler/typelimits.jl
@@ -432,6 +432,10 @@ function tmerge(@nospecialize(typea), @nospecialize(typeb))
         (uw isa DataType && ti <: uw.name.wrapper) || return Any
         typenames[i] = uw.name
     end
+    u = Union{types...}
+    if issimpleenoughtype(u)
+        return u
+    end
     # see if any of the union elements have the same TypeName
     # in which case, simplify this tmerge by replacing it with
     # the widest possible version of itself (the wrapper)
diff --git a/test/broadcast.jl b/test/broadcast.jl
index bebb072c5732ce..6e97d609a42b0d 100644
--- a/test/broadcast.jl
+++ b/test/broadcast.jl
@@ -955,18 +955,18 @@ p0 = copy(p)
     @test isequal([1, 2] .+ [3.0, missing], [4.0, missing])
     @test Core.Compiler.return_type(broadcast, Tuple{typeof(+), Vector{Int},
                                                      Vector{Union{Float64, Missing}}}) ==
-        Vector{<:Union{Float64, Missing}}
+        Union{Vector{Missing}, Vector{Union{Missing, Float64}}, Vector{Float64}}
     @test isequal([1, 2] + [3.0, missing], [4.0, missing])
     @test Core.Compiler.return_type(+, Tuple{Vector{Int},
                                              Vector{Union{Float64, Missing}}}) ==
-        Vector{<:Union{Float64, Missing}}
+        Union{Vector{Missing}, Vector{Union{Missing, Float64}}, Vector{Float64}}
     @test Core.Compiler.return_type(+, Tuple{Vector{Int},
                                              Vector{Union{Float64, Missing}}}) ==
-        Vector{<:Union{Float64, Missing}}
+        Union{Vector{Missing}, Vector{Union{Missing, Float64}}, Vector{Float64}}
     @test isequal(tuple.([1, 2], [3.0, missing]), [(1, 3.0), (2, missing)])
     @test Core.Compiler.return_type(broadcast, Tuple{typeof(tuple), Vector{Int},
                                                      Vector{Union{Float64, Missing}}}) ==
-        Vector{<:Tuple{Int, Any}}
+        Union{Vector{Tuple{Int, Missing}}, Vector{Tuple{Int, Any}}, Vector{Tuple{Int, Float64}}}
     # Check that corner cases do not throw an error
     @test isequal(broadcast(x -> x === 1 ? nothing : x, [1, 2, missing]),
                   [nothing, 2, missing])
diff --git a/test/compiler/codegen.jl b/test/compiler/codegen.jl
index 2b7b266751a087..47f419d9937a21 100644
--- a/test/compiler/codegen.jl
+++ b/test/compiler/codegen.jl
@@ -73,11 +73,13 @@ function test_jl_dump_compiles_toplevel_thunks()
     # Make sure to cause compilation of the eval function
     # before calling it below.
     Core.eval(Main, Any[:(nothing)][1])
+    GC.enable(false)  # avoid finalizers to be compiled
     topthunk = Meta.lower(Main, :(for i in 1:10; end))
     ccall(:jl_dump_compiles, Cvoid, (Ptr{Cvoid},), io.handle)
     Core.eval(Main, topthunk)
     ccall(:jl_dump_compiles, Cvoid, (Ptr{Cvoid},), C_NULL)
     close(io)
+    GC.enable(true)
     tstats = stat(tfile)
     tempty = tstats.size == 0
     rm(tfile)
diff --git a/test/compiler/inference.jl b/test/compiler/inference.jl
index 3ac749afaf9369..754fd7a3f5ce8c 100644
--- a/test/compiler/inference.jl
+++ b/test/compiler/inference.jl
@@ -103,10 +103,16 @@ tmerge_test(Tuple{ComplexF64, ComplexF64, ComplexF32}, Tuple{Vararg{Union{Comple
 tmerge_test(Tuple{}, Tuple{Complex, Vararg{Union{ComplexF32, ComplexF64}}},
     Tuple{Vararg{Complex}})
 @test Core.Compiler.tmerge(Tuple{}, Union{Nothing, Tuple{ComplexF32, ComplexF32}}) ==
+    Union{Nothing, Tuple{}, Tuple{ComplexF32, ComplexF32}}
+@test Core.Compiler.tmerge(Tuple{}, Union{Nothing, Tuple{ComplexF32}, Tuple{ComplexF32, ComplexF32}}) ==
     Union{Nothing, Tuple{Vararg{ComplexF32}}}
 @test Core.Compiler.tmerge(Union{Nothing, Tuple{ComplexF32}}, Union{Nothing, Tuple{ComplexF32, ComplexF32}}) ==
+    Union{Nothing, Tuple{ComplexF32}, Tuple{ComplexF32, ComplexF32}}
+@test Core.Compiler.tmerge(Union{Nothing, Tuple{}, Tuple{ComplexF32}}, Union{Nothing, Tuple{ComplexF32, ComplexF32}}) ==
     Union{Nothing, Tuple{Vararg{ComplexF32}}}
-@test Core.Compiler.tmerge(Vector{Int}, Core.Compiler.tmerge(Vector{String}, Vector{Bool})) == Vector
+@test Core.Compiler.tmerge(Vector{Int}, Core.Compiler.tmerge(Vector{String}, Vector{Bool})) ==
+    Union{Vector{Bool}, Vector{Int}, Vector{String}}
+@test Core.Compiler.tmerge(Vector{Int}, Core.Compiler.tmerge(Vector{String}, Union{Vector{Bool}, Vector{Symbol}})) == Vector
 @test Core.Compiler.tmerge(Base.BitIntegerType, Union{}) === Base.BitIntegerType
 @test Core.Compiler.tmerge(Union{}, Base.BitIntegerType) === Base.BitIntegerType
 @test Core.Compiler.tmerge(Core.Compiler.InterConditional(1, Int, Union{}), Core.Compiler.InterConditional(2, String, Union{})) === Core.Compiler.Const(true)
@@ -3227,3 +3233,13 @@ end
         return y
     end == Any[Union{Nothing, Tuple{String, Union{Nothing, String}}}]
 end
+
+@test Base.return_types((Int,)) do x
+    if x === 0
+        Some(0.0)
+    elseif x == 1
+        Some(1)
+    else
+        Some(0x2)
+    end
+end == [Union{Some{Float64}, Some{Int}, Some{UInt8}}]
diff --git a/test/worlds.jl b/test/worlds.jl
index deec2489de11c2..692f4febd91cdc 100644
--- a/test/worlds.jl
+++ b/test/worlds.jl
@@ -89,8 +89,8 @@ B265(x::Any, dummy::Nothing) = B265{UInt8}(x, dummy)
 @test (B265_(2)::B265{Float64}).field1 === 2.0e0
 @test (B265_(3)::B265{UInt8}).field1 === 0x03
 
-@test Base.return_types(B265_, (Int,)) == Any[B265]
-@test Core.Compiler.return_type(B265_, (Int,)) == B265
+@test B265{UInt8} <: only(Base.return_types(B265_, (Int,))) <: B265
+@test B265{UInt8} <: Core.Compiler.return_type(B265_, (Int,)) <: B265
 
 
 # test oldworld call / inference