[Expr] Don't use type info

[KDr2]

No description provided.

[KDr2]

Benchmark on this PR:

benchmarking rosenbrock...
  Run Original Function:  467.236 μs (16 allocations: 6.10 MiB)
  Run TapedFunction:  482.086 μs (52 allocations: 6.10 MiB)
  Run TapedFunction (compiled):  487.825 μs (79 allocations: 6.11 MiB)
benchmarking ackley...
  Run Original Function:  1.275 ms (0 allocations: 0 bytes)
  Run TapedFunction:  536.914 ms (1999019 allocations: 35.08 MiB)
  Run TapedFunction (compiled):  492.542 ms (3799046 allocations: 103.75 MiB)
benchmarking matrix_test...
  Run Original Function:  121.009 μs (16 allocations: 469.22 KiB)
  Run TapedFunction:  137.898 μs (46 allocations: 469.92 KiB)
  Run TapedFunction (compiled):  141.478 μs (76 allocations: 471.23 KiB)
benchmarking neural_net...
  Run Original Function:  512.078 ns (4 allocations: 576 bytes)
  Run TapedFunction:  2.732 μs (28 allocations: 1.62 KiB)
  Run TapedFunction (compiled):  2.953 μs (36 allocations: 1.91 KiB)
done

Benchmark on master:

benchmarking rosenbrock...
  Run Original Function:  469.646 μs (16 allocations: 6.10 MiB)
  Run TapedFunction:  514.965 μs (282 allocations: 6.11 MiB)
  Run TapedFunction (compiled):  486.386 μs (309 allocations: 6.11 MiB)
benchmarking ackley...
  Run Original Function:  1.271 ms (0 allocations: 0 bytes)
  Run TapedFunction:  666.093 ms (16698219 allocations: 445.53 MiB)
  Run TapedFunction (compiled):  624.690 ms (18498246 allocations: 592.02 MiB)
benchmarking matrix_test...
  Run Original Function:  127.299 μs (16 allocations: 469.22 KiB)
  Run TapedFunction:  144.548 μs (322 allocations: 477.91 KiB)
  Run TapedFunction (compiled):  148.279 μs (352 allocations: 480.67 KiB)
benchmarking neural_net...
  Run Original Function:  497.624 ns (4 allocations: 576 bytes)
  Run TapedFunction:  4.433 μs (75 allocations: 3.06 KiB)
  Run TapedFunction (compiled):  3.939 μs (83 allocations: 3.73 KiB)
done

[yebai]

Closed in favour of #138