Merge pull request #1837 from JuliaSymbolics/as/better-error-type

refactor: throw a better error for unimplemented functions in `codegen_function`

Author: AayushSabharwal

src/codegen_fn.jl

@@ -1,6 +1,14 @@
+struct FunctionUnimplementedError <: Exception
+    type::String
+end
+
+function Base.showerror(io::IO, err::FunctionUnimplementedError)
+    print(io, "The $(err.type) version for this function is invalid")
+end
+
 function get_unimplemented_fn(nargs, type)
     expr = :(function unimplemented()
-        error("The $($type) version for this function is invalid")
+        throw($FunctionUnimplementedError($type))
      end)
 
     for i in 1:nargs

test/codegen_function.jl

@@ -68,11 +68,11 @@ end
     out_2 = similar(out_1)
     h_ip!(out_1, inputs...)
     h_julia!(out_2, inputs...)
-    @test_throws ErrorException h3_oop(inputs...)
+    @test_throws Symbolics.FunctionUnimplementedError h3_oop(inputs...)
     @test out_1 == out_2
     h3_ip(out_1, inputs...)
     @test out_1 == out_2
-    @test_throws ErrorException h4_ip(out_1, inputs...)
+    @test_throws Symbolics.FunctionUnimplementedError h4_ip(out_1, inputs...)
     @test h4_oop(inputs...) == h_julia(inputs...)
     out_1 = similar(h, Int)
     fill!(out_1, 10)