Fix hasmissing dispatches (#368) (#369)

Fixes #368.

Author: devmotion

Project.toml

@@ -1,6 +1,6 @@
 name = "DynamicPPL"
 uuid = "366bfd00-2699-11ea-058f-f148b4cae6d8"
-version = "0.17.4"
+version = "0.17.5"
 
 [deps]
 AbstractMCMC = "80f14c24-f653-4e6a-9b94-39d6b0f70001"

src/compiler.jl

@@ -546,9 +546,10 @@ function make_returns_explicit!(body::Expr)
 end
 
 const FloatOrArrayType = Type{<:Union{AbstractFloat,AbstractArray}}
-hasmissing(T::Type{<:AbstractArray{TA}}) where {TA<:AbstractArray} = hasmissing(TA)
-hasmissing(T::Type{<:AbstractArray{>:Missing}}) = true
-hasmissing(T::Type) = false
+hasmissing(::Type) = false
+hasmissing(::Type{>:Missing}) = true
+hasmissing(::Type{<:AbstractArray{TA}}) where {TA} = hasmissing(TA)
+hasmissing(::Type{Union{}}) = false # issue #368
 
 """
     build_output(modelinfo, linenumbernode)

test/compiler.jl

@@ -588,4 +588,18 @@ end
         @model outer() = @submodel x = inner()
         @test outer()() isa Real
     end
+
+    @testset "issue #368: hasmissing dispatch" begin
+        @test !DynamicPPL.hasmissing(typeof(Union{}[]))
+
+        # (nested) arrays with `Missing` eltypes
+        @test DynamicPPL.hasmissing(Vector{Union{Missing,Float64}})
+        @test DynamicPPL.hasmissing(Matrix{Union{Missing,Real}})
+        @test DynamicPPL.hasmissing(Vector{Matrix{Union{Missing,Float32}}})
+
+        # no `Missing`
+        @test !DynamicPPL.hasmissing(Vector{Float64})
+        @test !DynamicPPL.hasmissing(Matrix{Real})
+        @test !DynamicPPL.hasmissing(Vector{Matrix{Float32}})
+    end
 end