Add missing non-existent src_base diagnostics

1 files changed, 13 insertions, 0 deletions

diff --git a/build2/b.cxx b/build2/b.cxx
index 4a764e6..8d06a72 100644
--- a/build2/b.cxx
+++ b/build2/b.cxx
@@ -587,8 +587,21 @@ main (int argc, char* argv[])
           // out. If src_base is still undetermined, calculate it.
           //
           if (src_base.empty ())
+          {
             src_base = src_root / out_base.leaf (out_root);
 
+            if (!exists (src_base))
+            {
+              diag_record dr;
+              dr << fail << "src_base directory " << src_base
+                 << " does not exist";
+
+              if (guessing)
+                dr << info << "consider explicitly specifying src_base "
+                   << "for " << tn;
+            }
+          }
+
           // Check that out_root that we have found is the innermost root
           // for this project. If it is not, then it means we are trying
           // to load a disfigured sub-project and that we do not support.