Features: Add dialect compile flags only if default is known.

The CMAKE_<LANG>_STANDARD_DEFAULT variable indicates whether the
compiler has any notion of standard levels and that CMake knows
about them.  If no language standard levels are available, skip
all logic to attempt to add a flag for the level.

Also fail with an internal error if a bad default value is set.

1 files changed, 9 insertions, 9 deletions

diff --git a/Source/cmLocalGenerator.cxx b/Source/cmLocalGenerator.cxx
index af4c950..81e37f6 100644
--- a/Source/cmLocalGenerator.cxx
+++ b/Source/cmLocalGenerator.cxx
@@ -2209,7 +2209,7 @@ AddCompilerRequirementFlag(std::string &flags, cmTarget* target,
     }
   const char* defaultStd
       = this->Makefile->GetDefinition("CMAKE_" + lang + "_STANDARD_DEFAULT");
-  if (defaultStd && !*defaultStd)
+  if (!defaultStd || !*defaultStd)
     {
     // This compiler has no notion of language standard levels.
     return;
@@ -2276,15 +2276,15 @@ AddCompilerRequirementFlag(std::string &flags, cmTarget* target,
                                 std::find(stds.begin(), stds.end(), standard);
   assert(stdIt != stds.end());
 
-  std::vector<std::string>::const_iterator defaultStdIt;
-  if (defaultStd)
+  std::vector<std::string>::const_iterator defaultStdIt =
+    std::find(stds.begin(), stds.end(), defaultStd);
+  if (defaultStdIt == stds.end())
     {
-    defaultStdIt = std::find(stds.begin(), stds.end(), defaultStd);
-    assert(defaultStdIt != stds.end());
-    }
-  else
-    {
-    defaultStdIt = stds.end() - 1;
+    std::string e =
+      "CMAKE_" + lang + "_STANDARD_DEFAULT is set to invalid value '" +
+      std::string(defaultStd) + "'";
+    this->Makefile->IssueMessage(cmake::INTERNAL_ERROR, e);
+    return;
     }
 
   for ( ; stdIt <= defaultStdIt; ++stdIt)