Add test for nested (non-toplevel) model

Author: phipsgabler

test/compiler.jl

@@ -213,6 +213,22 @@ priors = 0 # See "new grammar" test.
         @test getlogp(varinfo) == lp
         @test varinfo === _varinfo
     end
+    @testset "nested model" begin
+        function nest(α_0, θ_0)
+            @model gdemo(x) = begin
+                λ ~ Gamma(α_0, θ_0)
+                m ~ Normal(0, √(1 / λ))
+                x .~ Normal(m, √(1 / λ))
+                global lp = @logpdf()
+            end
+
+            return gdemo
+        end
+        model = nest(2.0, inv(3.0))([1.5, 2.0])
+        varinfo = DynamicPPL.VarInfo(model)
+        model(varinfo)
+        @test getlogp(varinfo) = lp
+    end
     @testset "new grammar" begin
         x = Float64[1 2]