From 4a74374e20d275722067e773d7ea99fc85ca2a0b Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Tue, 30 May 2017 14:11:50 +0200
Subject: Diagnose lack of module support in extract_modules()

---
 build2/cc/compile.cxx | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

(limited to 'build2/cc/compile.cxx')

diff --git a/build2/cc/compile.cxx b/build2/cc/compile.cxx
index ce96e00..c7fc3ea 100644
--- a/build2/cc/compile.cxx
+++ b/build2/cc/compile.cxx
@@ -610,9 +610,8 @@ namespace build2
 
         dd.close ();
 
-        // If C++ modules support is enabled then we need to extract the
-        // module dependency information in addition to header dependencies
-        // above.
+        // Extract the module dependency information in addition to header
+        // dependencies above.
         //
         if (u) // @@ TMP (depdb validation similar to extract_headers()).
         {
@@ -2207,8 +2206,16 @@ namespace build2
         throw failed ();
       }
 
-      if (!tu.module_name.empty () || !tu.module_imports.empty ())
-        fail << "module support not yet implemented";
+      //@@ TODO: if bmi{}, make sure module_name is not empty.
+
+      if (tu.module_name.empty () && tu.module_imports.empty ())
+        return;
+
+      // Modules are used by this translation unit. Make sure module support
+      // is enabled.
+      //
+      if (!modules)
+        fail << "modules support not enabled or unavailable";
     }
 
     // Filter cl.exe noise (msvc.cxx).
-- 
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