VS: Isolate custom command input/output generation scopes

Source/cmVisualStudio10TargetGenerator.cxx

@@ -1354,22 +1354,26 @@ void cmVisualStudio10TargetGenerator::WriteCustomRule(
     std::string script = lg->ConstructScript(ccg);
     // input files for custom command
     std::stringstream inputs;
-    inputs << source->GetFullPath();
-    for (std::string const& d : ccg.GetDepends()) {
-      std::string dep;
-      if (lg->GetRealDependency(d, c, dep)) {
-        ConvertToWindowsSlash(dep);
-        inputs << ";" << dep;
+    {
+      inputs << source->GetFullPath();
+      for (std::string const& d : ccg.GetDepends()) {
+        std::string dep;
+        if (lg->GetRealDependency(d, c, dep)) {
+          ConvertToWindowsSlash(dep);
+          inputs << ";" << dep;
+        }
       }
     }
     // output files for custom command
     std::stringstream outputs;
-    const char* sep = "";
-    for (std::string const& o : ccg.GetOutputs()) {
-      std::string out = o;
-      ConvertToWindowsSlash(out);
-      outputs << sep << out;
-      sep = ";";
+    {
+      const char* sep = "";
+      for (std::string const& o : ccg.GetOutputs()) {
+        std::string out = o;
+        ConvertToWindowsSlash(out);
+        outputs << sep << out;
+        sep = ";";
+      }
     }
     if (this->ProjectType == csproj) {
       std::string name = "CustomCommand_" + c + "_" +