Add regression test for #3902

Closes #3902.
Update test for #5543

Closes #5543.
Regression test for #8874

Closes #8874.
Regression test for simple case of #9197
Regression test for #13655

Closes #13655.
Regression test for #13665

Closes #13665.
Regression test for #13808

Closes #13808.
Regression tests for #13853

Closes #13853, #14889.
Regression test for #14386

Closes #14386.
Regression test for #14227

Closes #14227.
Regression test for #15034

Closes #15034.
Regression test for #16538

Closes #16538.
Regression test for #17728

Closes #17728.
Regression test for #17740

Closes #17740.
auto merge of #20165 : tamird/rust/needstest-tests, r=alexcrichton

@alexcrichton @jakub-