diff --git a/libgrust/libproc_macro/group.cc b/libgrust/libproc_macro/group.cc
index c5948ed03c7..9394387f636 100644
--- a/libgrust/libproc_macro/group.cc
+++ b/libgrust/libproc_macro/group.cc
@@ -22,6 +22,7 @@
 
 #include "group.h"
 
+namespace ProcMacro {
 namespace Group {
 
 Group
@@ -37,3 +38,4 @@ Group::drop (Group *g)
 }
 
 } // namespace Group
+} // namespace ProcMacro
diff --git a/libgrust/libproc_macro/group.h b/libgrust/libproc_macro/group.h
index bf2a23ff3ec..51913253550 100644
--- a/libgrust/libproc_macro/group.h
+++ b/libgrust/libproc_macro/group.h
@@ -25,6 +25,7 @@
 
 #include "tokenstream.h"
 
+namespace ProcMacro {
 namespace Group {
 
 enum Delimiter
@@ -47,5 +48,6 @@ public:
 };
 
 } // namespace Group
+} // namespace ProcMacro
 
 #endif /* ! GROUP_H */
diff --git a/libgrust/libproc_macro/ident.cc b/libgrust/libproc_macro/ident.cc
index 0bed2a8e7d4..6fe8676d45f 100644
--- a/libgrust/libproc_macro/ident.cc
+++ b/libgrust/libproc_macro/ident.cc
@@ -23,6 +23,7 @@
 
 #include <cstring>
 
+namespace ProcMacro {
 namespace Ident {
 
 extern "C" {
@@ -84,3 +85,4 @@ Ident::drop (Ident *ident)
 }
 
 } // namespace Ident
+} // namespace ProcMacro
diff --git a/libgrust/libproc_macro/ident.h b/libgrust/libproc_macro/ident.h
index 0e21275863e..0c89185f306 100644
--- a/libgrust/libproc_macro/ident.h
+++ b/libgrust/libproc_macro/ident.h
@@ -26,6 +26,7 @@
 #include <cstdint>
 #include <string>
 
+namespace ProcMacro {
 namespace Ident {
 
 struct Ident
@@ -61,5 +62,6 @@ Ident__clone (const Ident *ident);
 }
 
 } // namespace Ident
+} // namespace ProcMacro
 
 #endif /* ! IDENT_H */
diff --git a/libgrust/libproc_macro/literal.cc b/libgrust/libproc_macro/literal.cc
index d4977533a90..13b97a9417d 100644
--- a/libgrust/libproc_macro/literal.cc
+++ b/libgrust/libproc_macro/literal.cc
@@ -24,6 +24,7 @@
 #include <cstring>
 #include <cstdlib>
 
+namespace ProcMacro {
 namespace Literal {
 
 void
@@ -289,3 +290,4 @@ Literal::make_isize (std::int64_t value, bool suffixed)
 }
 
 } // namespace Literal
+} // namespace ProcMacro
diff --git a/libgrust/libproc_macro/literal.h b/libgrust/libproc_macro/literal.h
index 2c61231e8b2..15d40e06620 100644
--- a/libgrust/libproc_macro/literal.h
+++ b/libgrust/libproc_macro/literal.h
@@ -27,6 +27,7 @@
 #include <string>
 #include <vector>
 
+namespace ProcMacro {
 namespace Literal {
 enum UnsignedTag
 {
@@ -207,5 +208,6 @@ Literal__from_string (const unsigned char *str, std::uint64_t len,
 		      Literal *lit);
 }
 } // namespace Literal
+} // namespace ProcMacro
 
 #endif /* ! LITERAL_H */
diff --git a/libgrust/libproc_macro/punct.cc b/libgrust/libproc_macro/punct.cc
index 67d35fec5a8..762d6424f94 100644
--- a/libgrust/libproc_macro/punct.cc
+++ b/libgrust/libproc_macro/punct.cc
@@ -23,6 +23,7 @@
 #include "punct.h"
 #include <cstdlib>
 
+namespace ProcMacro {
 namespace Punct {
 
 Punct
@@ -32,3 +33,4 @@ Punct::make_punct (std::uint32_t ch, Spacing spacing)
 }
 
 } // namespace Punct
+} // namespace ProcMacro
diff --git a/libgrust/libproc_macro/punct.h b/libgrust/libproc_macro/punct.h
index 0e5e42f674d..b9098b1e279 100644
--- a/libgrust/libproc_macro/punct.h
+++ b/libgrust/libproc_macro/punct.h
@@ -25,6 +25,7 @@
 
 #include <cstdint>
 
+namespace ProcMacro {
 namespace Punct {
 
 enum Spacing
@@ -43,5 +44,6 @@ public:
 };
 
 } // namespace Punct
+} // namespace ProcMacro
 
 #endif /* ! PUNCT_H */
diff --git a/libgrust/libproc_macro/tokenstream.cc b/libgrust/libproc_macro/tokenstream.cc
index 921cc22bf13..68e72666691 100644
--- a/libgrust/libproc_macro/tokenstream.cc
+++ b/libgrust/libproc_macro/tokenstream.cc
@@ -25,6 +25,7 @@
 
 #include <cstring>
 
+namespace ProcMacro {
 namespace TokenStream {
 
 TokenStream
@@ -117,3 +118,4 @@ TokenStream__drop (TokenStream *stream)
 }
 
 } // namespace TokenStream
+} // namespace ProcMacro
diff --git a/libgrust/libproc_macro/tokenstream.h b/libgrust/libproc_macro/tokenstream.h
index 909e6f441b2..ac88f8047e3 100644
--- a/libgrust/libproc_macro/tokenstream.h
+++ b/libgrust/libproc_macro/tokenstream.h
@@ -26,6 +26,7 @@
 #include <cstdint>
 #include <vector>
 
+namespace ProcMacro {
 namespace TokenTree {
 struct TokenTree;
 }
@@ -73,5 +74,6 @@ extern "C" void
 TokenStream__drop (TokenStream *stream);
 
 } // namespace TokenStream
+} // namespace ProcMacro
 
 #endif /* ! TOKENSTREAM_H */
diff --git a/libgrust/libproc_macro/tokentree.cc b/libgrust/libproc_macro/tokentree.cc
index 924e50c6f3b..408828ba1f2 100644
--- a/libgrust/libproc_macro/tokentree.cc
+++ b/libgrust/libproc_macro/tokentree.cc
@@ -22,6 +22,7 @@
 
 #include "tokentree.h"
 
+namespace ProcMacro {
 namespace TokenTree {
 
 TokenTree
@@ -76,3 +77,4 @@ TokenTree::drop (TokenTree *tt)
 }
 
 } // namespace TokenTree
+} // namespace ProcMacro
diff --git a/libgrust/libproc_macro/tokentree.h b/libgrust/libproc_macro/tokentree.h
index 86fc5eb2688..ada1557efd9 100644
--- a/libgrust/libproc_macro/tokentree.h
+++ b/libgrust/libproc_macro/tokentree.h
@@ -28,6 +28,7 @@
 #include "punct.h"
 #include "literal.h"
 
+namespace ProcMacro {
 namespace TokenTree {
 
 enum TokenTreeTag
@@ -61,5 +62,6 @@ public:
 };
 
 } // namespace TokenTree
+} // namespace ProcMacro
 
 #endif /* ! TOKENTREE_H */