Index: clang-tools-extra/trunk/clangd/URI.cpp
===================================================================
--- clang-tools-extra/trunk/clangd/URI.cpp
+++ clang-tools-extra/trunk/clangd/URI.cpp
@@ -79,7 +79,8 @@
 
 bool shouldEscape(unsigned char C) {
   // Unreserved characters.
-  if ((C >= 'a' && C <= 'z') || (C >= 'A' && C <= 'Z'))
+  if ((C >= 'a' && C <= 'z') || (C >= 'A' && C <= 'Z') ||
+      (C >= '0' && C <= '9'))
     return false;
   switch (C) {
   case '-':
Index: clang-tools-extra/trunk/unittests/clangd/URITests.cpp
===================================================================
--- clang-tools-extra/trunk/unittests/clangd/URITests.cpp
+++ clang-tools-extra/trunk/unittests/clangd/URITests.cpp
@@ -72,6 +72,7 @@
 TEST(PercentEncodingTest, Encode) {
   EXPECT_EQ(URI("x", /*Authority=*/"", "a/b/c").toString(), "x:a/b/c");
   EXPECT_EQ(URI("x", /*Authority=*/"", "a!b;c~").toString(), "x:a%21b%3bc~");
+  EXPECT_EQ(URI("x", /*Authority=*/"", "a123b").toString(), "x:a123b");
 }
 
 TEST(PercentEncodingTest, Decode) {