diff --git a/tools/gn/args.cc b/tools/gn/args.cc
index 967a65e..bd0db35 100644
--- a/tools/gn/args.cc
+++ b/tools/gn/args.cc
@@ -248,7 +248,7 @@
   std::string err_help(
       "The variable \"" + name + "\" was set as a build argument\n"
       "but never appeared in a declare_args() block in any buildfile.\n\n"
-      "To view all possible args, run \"gn args --list <builddir>\"");
+      "To view all possible args, run \"gn args --list <out_dir>\"");
 
   // Use all declare_args for a spelling suggestion.
   std::vector<base::StringPiece> candidates;
diff --git a/tools/gn/err.cc b/tools/gn/err.cc
index 56e93bd..362bfb0 100644
--- a/tools/gn/err.cc
+++ b/tools/gn/err.cc
@@ -150,18 +150,26 @@
 }
 
 void Err::PrintToStdout() const {
-  InternalPrintToStdout(false);
+  InternalPrintToStdout(false, true);
+}
+
+void Err::PrintNonfatalToStdout() const {
+  InternalPrintToStdout(false, false);
 }
 
 void Err::AppendSubErr(const Err& err) {
   sub_errs_.push_back(err);
 }
 
-void Err::InternalPrintToStdout(bool is_sub_err) const {
+void Err::InternalPrintToStdout(bool is_sub_err, bool is_fatal) const {
   DCHECK(has_error_);
 
-  if (!is_sub_err)
-    OutputString("ERROR ", DECORATION_RED);
+  if (!is_sub_err) {
+    if (is_fatal)
+      OutputString("ERROR ", DECORATION_RED);
+    else
+      OutputString("WARNING ", DECORATION_RED);
+  }
 
   // File name and location.
   const InputFile* input_file = location_.file();
@@ -191,5 +199,5 @@
 
   // Sub errors.
   for (const auto& sub_err : sub_errs_)
-    sub_err.InternalPrintToStdout(true);
+    sub_err.InternalPrintToStdout(true, is_fatal);
 }
diff --git a/tools/gn/err.h b/tools/gn/err.h
index eeec31a..90f3150 100644
--- a/tools/gn/err.h
+++ b/tools/gn/err.h
@@ -24,7 +24,7 @@
 // below. They can provide additional context.
 class Err {
  public:
-  typedef std::vector<LocationRange> RangeList;
+  using RangeList = std::vector<LocationRange>;
 
   // Indicates no error.
   Err();
@@ -70,8 +70,20 @@
 
   void PrintToStdout() const;
 
+  // Prints to standard out but uses a "WARNING" messaging instead of the
+  // normal "ERROR" messaging. This is a property of the printing system rather
+  // than of the Err class because there is no expectation that code calling a
+  // function that take an Err check that the error is nonfatal and continue.
+  // Generally all Err objects with has_error() set are fatal.
+  //
+  // In some very specific cases code will detect a condition and print a
+  // nonfatal error to the screen instead of returning it. In these cases, that
+  // code can decide at printing time whether it will continue (and use this
+  // method) or not (and use PrintToStdout()).
+  void PrintNonfatalToStdout() const;
+
  private:
-  void InternalPrintToStdout(bool is_sub_err) const;
+  void InternalPrintToStdout(bool is_sub_err, bool is_fatal) const;
 
   bool has_error_;
   Location location_;
diff --git a/tools/gn/setup.cc b/tools/gn/setup.cc
index a448d92..e3b01a4 100644
--- a/tools/gn/setup.cc
+++ b/tools/gn/setup.cc
@@ -371,13 +371,14 @@
   }
 
   if (!build_settings_.build_args().VerifyAllOverridesUsed(&err)) {
-    // TODO(brettw) implement a system to have a different marker for
-    // warnings. Until we have a better system, print the error but don't
-    // return failure unless requested on the command line.
-    err.PrintToStdout();
     if (base::CommandLine::ForCurrentProcess()->HasSwitch(
-            switches::kFailOnUnusedArgs))
+            switches::kFailOnUnusedArgs)) {
+      err.PrintToStdout();
       return false;
+    }
+    err.PrintNonfatalToStdout();
+    OutputString("\nThe build continued as if that argument was "
+                 "unspecified.\n\n");
     return true;
   }