tests

Author: mcabbott

src/compiler/chainrules.jl

@@ -155,6 +155,9 @@ The two-argument `_project(x, dx)` applies this immediately.
 # 
 # But the original case was an array of Union{Int,Nothing}
 
+# Solve some ambiguity:
+(::ProjectTo{ChainRulesCore.NoTangent})(::ChainRulesCore.AbstractZero) = NoTangent()
+
 """
   ZBack{F}(back) <: Function
 

test/gradcheck.jl

@@ -1678,7 +1678,7 @@ end
     # check that type is not unnecessarily promoted
     # https://github.com/FluxML/Zygote.jl/issues/663
     @test gradient(norm, randn(Float32, 2, 2)) isa Tuple{Matrix{Float32}}
-    @test gradient(norm, randn(Float32, 2, 2), 3) isa Tuple{Matrix{Float32},Float32}
+    @test gradient(norm, randn(Float32, 2, 2), 3) isa Tuple{Matrix{Float32},Float64}
     @test gradient(norm, randn(Float32, 2, 2), 3f0) isa Tuple{Matrix{Float32},Float32}
     @test gradient(norm, randn(ComplexF32, 2, 2), 3.5f0) isa Tuple{Matrix{ComplexF32},Float32}