Complain if signatures of the forward declaration and generated code mismatch

[vgvassilev]

Clad builds a gradient with a specific signature. It also allows that gradient function signature to be forward-declared. However if both mismatch there are subtle crashes in CodeGen. We should detect such cases and issue an error if they are in the same translation unit:

For example,

clad/test/Gradient/Gradients.C

Line 269 in d7e5434

//CHECK: void f_cond3_grad(double x, double c, clad::array_ref<double> _d_x, clad::array_ref<double> _d_c) {

returns void, but the forward declaration is:

clad/test/Gradient/Gradients.C

Line 283 in d7e5434

double f_cond3_grad(double x, double c, clad::array_ref<double> _d_x, clad::array_ref<double> _d_y);

which leads to subtle issues.

[kaushal-malpure]

Hi @vgvassilev ,
Can I contribute to this issue?

[vgvassilev]

@kaushal-malpure, please select one issue and solve it, please do not write under every open issue.