diff --git a/compiler/cpp/src/main.cc b/compiler/cpp/src/main.cc
index 0674594..5e218b4 100644
--- a/compiler/cpp/src/main.cc
+++ b/compiler/cpp/src/main.cc
@@ -657,6 +657,20 @@
 }
 
 /**
+ * Prints deprecation notice for old NS declarations that are no longer supported
+ * If new_form is NULL, old_form is assumed to be a language identifier, such as "cpp"
+ * If new_form is not NULL, both arguments are used exactly as given
+ */
+void error_unsupported_namespace_decl(char* old_form, char* new_form) {
+  char* remainder = "";
+  if( new_form == NULL) {
+    new_form = old_form;
+    remainder = "_namespace";
+  }
+  failure("Unsupported declaration '%s%s'. Use 'namespace %s' instead.", old_form, remainder, new_form);
+}
+
+/**
  * Prints the version number
  */
 void version() {
diff --git a/compiler/cpp/src/main.h b/compiler/cpp/src/main.h
index 8751dd5..98ca754 100644
--- a/compiler/cpp/src/main.h
+++ b/compiler/cpp/src/main.h
@@ -102,6 +102,13 @@
 void emit_byte_type_warning();
 
 /**
+ * Prints deprecation notice for old NS declarations that are no longer supported
+ * If new_form is NULL, old_form is assumed to be a language identifier, such as "cpp"
+ * If new_form is not NULL, both arguments are used exactly as given
+ */
+void error_unsupported_namespace_decl(char* old_form, char* new_form = NULL);
+
+/**
  * Flex utilities
  */
 
diff --git a/compiler/cpp/src/thriftl.ll b/compiler/cpp/src/thriftl.ll
index 7d96bca..76acda1 100644
--- a/compiler/cpp/src/thriftl.ll
+++ b/compiler/cpp/src/thriftl.ll
@@ -134,23 +134,23 @@
 "true"               { yylval.iconst=1; return tok_int_constant; }
 
 "namespace"          { return tok_namespace;            }
-"cpp_namespace"      { return tok_cpp_namespace;        }
+"cpp_namespace"      { error_unsupported_namespace_decl("cpp"); /* do nothing */ }
 "cpp_include"        { return tok_cpp_include;          }
 "cpp_type"           { return tok_cpp_type;             }
-"java_package"       { return tok_java_package;         }
-"cocoa_prefix"       { return tok_cocoa_prefix;         }
-"csharp_namespace"   { return tok_csharp_namespace;     }
-"delphi_namespace"   { return tok_delphi_namespace;     }
-"php_namespace"      { return tok_php_namespace;        }
-"py_module"          { return tok_py_module;            }
-"perl_package"       { return tok_perl_package;         }
-"ruby_namespace"     { return tok_ruby_namespace;       }
-"smalltalk_category" { return tok_smalltalk_category;   }
-"smalltalk_prefix"   { return tok_smalltalk_prefix;     }
+"java_package"       { error_unsupported_namespace_decl("java_package", "java"); /* do nothing */ }
+"cocoa_prefix"       { error_unsupported_namespace_decl("cocoa_prefix", "cocoa"); /* do nothing */ }
+"csharp_namespace"   { error_unsupported_namespace_decl("csharp"); /* do nothing */ }
+"delphi_namespace"   { error_unsupported_namespace_decl("delphi"); /* do nothing */ }
+"php_namespace"      { error_unsupported_namespace_decl("php"); /* do nothing */ }
+"py_module"          { error_unsupported_namespace_decl("py_module", "py"); /* do nothing */ }
+"perl_package"       { error_unsupported_namespace_decl("perl_package", "perl"); /* do nothing */ }
+"ruby_namespace"     { error_unsupported_namespace_decl("ruby"); /* do nothing */ }
+"smalltalk_category" { error_unsupported_namespace_decl("smalltalk_category", "smalltalk.category"); /* do nothing */ }
+"smalltalk_prefix"   { error_unsupported_namespace_decl("smalltalk_category", "smalltalk.category"); /* do nothing */ }
 "xsd_all"            { return tok_xsd_all;              }
 "xsd_optional"       { return tok_xsd_optional;         }
 "xsd_nillable"       { return tok_xsd_nillable;         }
-"xsd_namespace"      { return tok_xsd_namespace;        }
+"xsd_namespace"      { error_unsupported_namespace_decl("xsd"); /* do nothing */ }
 "xsd_attrs"          { return tok_xsd_attrs;            }
 "include"            { return tok_include;              }
 "void"               { return tok_void;                 }
diff --git a/compiler/cpp/src/thrifty.yy b/compiler/cpp/src/thrifty.yy
index 59f6b4f..546196a 100644
--- a/compiler/cpp/src/thrifty.yy
+++ b/compiler/cpp/src/thrifty.yy
@@ -112,24 +112,12 @@
  */
 %token tok_include
 %token tok_namespace
-%token tok_cpp_namespace
 %token tok_cpp_include
 %token tok_cpp_type
-%token tok_php_namespace
-%token tok_py_module
-%token tok_perl_package
-%token tok_java_package
 %token tok_xsd_all
 %token tok_xsd_optional
 %token tok_xsd_nillable
-%token tok_xsd_namespace
 %token tok_xsd_attrs
-%token tok_ruby_namespace
-%token tok_smalltalk_category
-%token tok_smalltalk_prefix
-%token tok_cocoa_prefix
-%token tok_csharp_namespace
-%token tok_delphi_namespace
 
 /**
  * Base datatype keywords
@@ -317,16 +305,6 @@
         g_program->set_namespace("*", $3);
       }
     }
-/* TODO(dreiss): Get rid of this once everyone is using the new hotness. */
-| tok_cpp_namespace tok_identifier
-    {
-      pwarning(1, "'cpp_namespace' is deprecated. Use 'namespace cpp' instead");
-      pdebug("Header -> tok_cpp_namespace tok_identifier");
-      declare_valid_program_doctext();
-      if (g_parse_mode == PROGRAM) {
-        g_program->set_namespace("cpp", $2);
-      }
-    }
 | tok_cpp_include tok_literal
     {
       pdebug("Header -> tok_cpp_include tok_literal");
@@ -335,115 +313,6 @@
         g_program->add_cpp_include($2);
       }
     }
-| tok_php_namespace tok_identifier
-    {
-      pwarning(1, "'php_namespace' is deprecated. Use 'namespace php' instead");
-      pdebug("Header -> tok_php_namespace tok_identifier");
-      declare_valid_program_doctext();
-      if (g_parse_mode == PROGRAM) {
-        g_program->set_namespace("php", $2);
-      }
-    }
-/* TODO(dreiss): Get rid of this once everyone is using the new hotness. */
-| tok_py_module tok_identifier
-    {
-      pwarning(1, "'py_module' is deprecated. Use 'namespace py' instead");
-      pdebug("Header -> tok_py_module tok_identifier");
-      declare_valid_program_doctext();
-      if (g_parse_mode == PROGRAM) {
-        g_program->set_namespace("py", $2);
-      }
-    }
-/* TODO(dreiss): Get rid of this once everyone is using the new hotness. */
-| tok_perl_package tok_identifier
-    {
-      pwarning(1, "'perl_package' is deprecated. Use 'namespace perl' instead");
-      pdebug("Header -> tok_perl_namespace tok_identifier");
-      declare_valid_program_doctext();
-      if (g_parse_mode == PROGRAM) {
-        g_program->set_namespace("perl", $2);
-      }
-    }
-/* TODO(dreiss): Get rid of this once everyone is using the new hotness. */
-| tok_ruby_namespace tok_identifier
-    {
-      pwarning(1, "'ruby_namespace' is deprecated. Use 'namespace rb' instead");
-      pdebug("Header -> tok_ruby_namespace tok_identifier");
-      declare_valid_program_doctext();
-      if (g_parse_mode == PROGRAM) {
-        g_program->set_namespace("rb", $2);
-      }
-    }
-/* TODO(dreiss): Get rid of this once everyone is using the new hotness. */
-| tok_smalltalk_category tok_st_identifier
-    {
-      pwarning(1, "'smalltalk_category' is deprecated. Use 'namespace smalltalk.category' instead");
-      pdebug("Header -> tok_smalltalk_category tok_st_identifier");
-      declare_valid_program_doctext();
-      if (g_parse_mode == PROGRAM) {
-        g_program->set_namespace("smalltalk.category", $2);
-      }
-    }
-/* TODO(dreiss): Get rid of this once everyone is using the new hotness. */
-| tok_smalltalk_prefix tok_identifier
-    {
-      pwarning(1, "'smalltalk_prefix' is deprecated. Use 'namespace smalltalk.prefix' instead");
-      pdebug("Header -> tok_smalltalk_prefix tok_identifier");
-      declare_valid_program_doctext();
-      if (g_parse_mode == PROGRAM) {
-        g_program->set_namespace("smalltalk.prefix", $2);
-      }
-    }
-/* TODO(dreiss): Get rid of this once everyone is using the new hotness. */
-| tok_java_package tok_identifier
-    {
-      pwarning(1, "'java_package' is deprecated. Use 'namespace java' instead");
-      pdebug("Header -> tok_java_package tok_identifier");
-      declare_valid_program_doctext();
-      if (g_parse_mode == PROGRAM) {
-        g_program->set_namespace("java", $2);
-      }
-    }
-/* TODO(dreiss): Get rid of this once everyone is using the new hotness. */
-| tok_cocoa_prefix tok_identifier
-    {
-      pwarning(1, "'cocoa_prefix' is deprecated. Use 'namespace cocoa' instead");
-      pdebug("Header -> tok_cocoa_prefix tok_identifier");
-      declare_valid_program_doctext();
-      if (g_parse_mode == PROGRAM) {
-        g_program->set_namespace("cocoa", $2);
-      }
-    }
-/* TODO(dreiss): Get rid of this once everyone is using the new hotness. */
-| tok_xsd_namespace tok_literal
-    {
-      pwarning(1, "'xsd_namespace' is deprecated. Use 'namespace xsd' instead");
-      pdebug("Header -> tok_xsd_namespace tok_literal");
-      declare_valid_program_doctext();
-      if (g_parse_mode == PROGRAM) {
-        g_program->set_namespace("cocoa", $2);
-      }
-    }
-/* TODO(dreiss): Get rid of this once everyone is using the new hotness. */
-| tok_csharp_namespace tok_identifier
-   {
-     pwarning(1, "'csharp_namespace' is deprecated. Use 'namespace csharp' instead");
-     pdebug("Header -> tok_csharp_namespace tok_identifier");
-     declare_valid_program_doctext();
-     if (g_parse_mode == PROGRAM) {
-       g_program->set_namespace("csharp", $2);
-     }
-   }
-/* TODO(dreiss): Get rid of this once everyone is using the new hotness. */
-| tok_delphi_namespace tok_identifier
-   {
-     pwarning(1, "'delphi_namespace' is deprecated. Use 'namespace delphi' instead");
-     pdebug("Header -> tok_delphi_namespace tok_identifier");
-     declare_valid_program_doctext();
-     if (g_parse_mode == PROGRAM) {
-       g_program->set_namespace("delphi", $2);
-     }
-   }
 
 Include:
   tok_include tok_literal