Attempt to fix #262 (#273)

Author: kshyatt

src/planar/preprocessors.jl

@@ -211,7 +211,7 @@ function _construct_braidingtensors!(ex, preargs, indexmap) # ex is guaranteed t
         newargs = Vector{Any}(undef, length(args))
         newargs[1] = args[1]
         success = true
-        indices = TO.getindices(ex)
+        indices = [TO.getindices(arg) for arg in args]
         for i in 2:length(ex.args)
             indexmapa = copy(indexmap)
             newargs[i], successa = _construct_braidingtensors!(args[i], preargs, indexmapa)

test/planar.jl

@@ -284,4 +284,13 @@ end
 
         @test tr1 ≈ tr2 ≈ tr3 ≈ tr4 ≈ tr5 ≈ tr6 ≈ tr7
     end
+    @testset "Issue 262" begin
+        V = ℂ^2
+        A = rand(T, V ← V)
+        B = rand(T, V ← V')
+        C = rand(T, V' ← V)
+        @planar D1[i; j] := A[i; j] + B[i; k] * C[k; j]
+        @planar D2[i; j] := B[i; k] * C[k; j] + A[i; j]
+        @test D1 ≈ D2
+    end
 end