Report error/warning if /pathmap doesn't cover all emitted source paths

[tmat]

Version Used:

2.7.0.62412 (84aeb8e)

Steps to Reproduce:

Create files C:\temp\a\x.cs and C:\temp\b\y.cs containing some methods.

C:\temp>csc a\x.cs b\y.cs /pathmap:C:\temp\a=/_/ /t:library /deterministic /debug:portable

The resulting binary (pdb) is not fully deterministic since not all paths in the pdb were mapped to a deterministic value.

Expected Behavior:

An error or warning is reported when both /deterministic and /pathmap are specified but the map doesn't cover all paths, so that the user knows that the given /pathmap is insufficient.

Actual Behavior:

No warning/error.

[tmat]

/cc @jaredpar