make set more hygienic, see https://github.com/jw3126/Setfield.jl/pull/156

Project.toml

@@ -1,7 +1,7 @@
 name = "Accessors"
 uuid = "7d9f7c33-5ae7-4f3b-8dc6-eff91059b697"
 authors = ["Takafumi Arakaki <[email protected]>", "Jan Weidner <[email protected]> and contributors"]
-version = "0.1.4"
+version = "0.1.5"
 
 [deps]
 Compat = "34da2185-b29b-5c13-b0c7-acf172513d20"

src/sugar.jl

@@ -88,10 +88,7 @@ See also [`opticmacro`](@ref), [`setmacro`](@ref).
 function modifymacro(optictransform, f, obj_optic)
     f = esc(f)
     obj, optic = parse_obj_optic(obj_optic)
-    :(let
-        optic = $(optictransform)($optic)
-        ($modify)($f, $obj, optic)
-    end)
+    :(($modify)($f, $obj, $(optictransform)($optic)))
 end
 
 foldtree(op, init, x) = op(init, x)
@@ -228,17 +225,11 @@ function setmacro(optictransform, ex::Expr; overwrite::Bool=false)
     dst = overwrite ? obj : gensym("_")
     val = esc(val)
     ret = if ex.head == :(=)
-        quote
-            optic = ($optictransform)($optic)
-            $dst = $set($obj, optic, $val)
-        end
+        :($dst = $set($obj, ($optictransform)($optic), $val))
     else
         op = get_update_op(ex.head)
         f = :($_UpdateOp($op,$val))
-        quote
-            optic = ($optictransform)($optic)
-            $dst = $modify($f, $obj, optic)
-        end
+        :($dst = $modify($f, $obj, ($optictransform)($optic)))
     end
     ret
 end

test/test_setmacro.jl

@@ -48,4 +48,35 @@ using StaticNumbers
     @test m3 === @SMatrix[1 0; 0 0]
 end
 
+# inference
+
+macro setfield156(expr)
+    # Example of macro that caused inference issues,
+    # see https://github.com/jw3126/Setfield.jl/pull/156
+    quote
+        function f($(esc(:x)))
+            $(Accessors.setmacro(identity, expr, overwrite=true))
+            $(Accessors.setmacro(identity, expr, overwrite=true))
+            $(Accessors.setmacro(identity, expr, overwrite=true))
+            $(Accessors.setmacro(identity, expr, overwrite=true))
+            $(Accessors.setmacro(identity, expr, overwrite=true))
+            return $(esc(:x))
+        end
+    end
+end
+
+function test_all_inferrable(f, argtypes)
+    # hacky, maybe JETTest can help?
+    # * JETTest.@test_nodispatch does not detect the problem
+    typed = first(code_typed(f, argtypes))
+    code = typed.first
+    @test all(T -> !(T isa UnionAll || T === Any), code.slottypes)
+end
+
+@testset "setmacro multiple usage" begin
+    let f = @setfield156(x[end] = 1)
+        test_all_inferrable(f, (Vector{Float64}, ))
+    end
+end
+
 end#module