fix promote

Author: shashi

src/controlflow.jl

@@ -221,6 +221,8 @@ function rewrite_ir(ctx, ref)
 
     ir.ssavaluetypes = length(ir.code)
     # Core.Compiler.validate_code(ir)
+    #@show ref.method
+    #@show ir
     return ir
 end
 

src/propagate_tags.jl

@@ -8,6 +8,17 @@ macro proptagcontext(name)
     quote
         Cassette.@context($name)
 
+        ## promote(x,y) should not tag the output tuple with the union of tags
+        ## of x and y. So here we recurse into promote, and then tag each
+        ## element of the result with the original tag
+        function Cassette.overdub(ctx::$name, f::typeof(promote), args...)
+            promoted = Cassette.recurse(ctx, f, args...)
+
+            # put the tags back on:
+            tagged_promoted = map((x,v)->tag(v, ctx, metadata(x, ctx)), args, promoted)
+            Cassette.overdub(ctx, tuple, tagged_promoted...)
+        end
+
         function Cassette.overdub(ctx::$name, f, args...)
             # this check can be inferred (in theory)
             if anytagged(args...)

test/examples.jl

@@ -13,4 +13,5 @@ using SparsityDetection, SparseArrays
 input = rand(10)
 output = similar(input)
 sparsity_pattern = sparsity!(f,output,input)
-jac = Float64.(sparse(sparsity_pattern))
+
+@test nnz(sparse(sparsity_pattern)) == 28