diff --git a/stdlib/public/StringProcessing/CMakeLists.txt b/stdlib/public/StringProcessing/CMakeLists.txt
index 7fefef92722d0..2a5a5a5eeaf5f 100644
--- a/stdlib/public/StringProcessing/CMakeLists.txt
+++ b/stdlib/public/StringProcessing/CMakeLists.txt
@@ -41,6 +41,7 @@ add_swift_target_library(swift_StringProcessing ${SWIFT_STDLIB_LIBRARY_BUILD_TYP
     -Dswift_StringProcessing_EXPORTS
   SWIFT_COMPILE_FLAGS
     ${SWIFT_STANDARD_LIBRARY_SWIFT_FLAGS}
+    -Xfrontend -enable-experimental-pairwise-build-block
   LINK_FLAGS "${SWIFT_RUNTIME_SWIFT_LINK_FLAGS}"
 
   SWIFT_MODULE_DEPENDS _MatchingEngine
diff --git a/test/StringProcessing/Runtime/regex_basic.swift b/test/StringProcessing/Runtime/regex_basic.swift
index fb0ee31d32775..697f4b7d886b5 100644
--- a/test/StringProcessing/Runtime/regex_basic.swift
+++ b/test/StringProcessing/Runtime/regex_basic.swift
@@ -11,7 +11,7 @@ extension String {
     _ regex: Regex<T>,
     file: String = #file,
     line: UInt = #line
-  ) -> RegexMatch<T> {
+  ) -> Regex<T>.Match {
     guard let result = match(regex) else {
       expectUnreachable("Failed match", file: file, line: line)
       fatalError()
@@ -24,20 +24,20 @@ RegexBasicTests.test("Basic") {
   let input = "aabccd"
 
   let match1 = input.expectMatch(#/aabcc./#)
-  expectEqual("aabccd", input[match1.range])
-  expectTrue("aabccd" == match1.match)
+  expectEqual("aabccd", match1.0)
+  expectTrue("aabccd" == match1.output)
 
   let match2 = input.expectMatch(#/a*b.+./#)
-  expectEqual("aabccd", input[match2.range])
-  expectTrue("aabccd" == match2.match)
+  expectEqual("aabccd", match2.0)
+  expectTrue("aabccd" == match2.output)
 }
 
 RegexBasicTests.test("Modern") {
   let input = "aabccd"
 
   let match1 = input.expectMatch(#|a a  bc c /*hello*/ .|#)
-  expectEqual("aabccd", input[match1.range])
-  expectTrue("aabccd" == match1.match)
+  expectEqual("aabccd", match1.0)
+  expectTrue("aabccd" == match1.output)
 }
 
 RegexBasicTests.test("Captures") {
@@ -50,7 +50,7 @@ RegexBasicTests.test("Captures") {
   let _: Regex<(Substring, Substring, Substring?, Substring)>.Type
     = type(of: regex)
   let match1 = input.expectMatch(regex)
-  expectEqual(input[...], input[match1.range])
+  expectEqual(input[...], match1.0)
   expectTrue(input == match1.0)
   expectTrue("A6F0" == match1.1)
   expectTrue("A6F1" == match1.2)
diff --git a/test/StringProcessing/Sema/regex_literal_type_inference.swift b/test/StringProcessing/Sema/regex_literal_type_inference.swift
index bd645850886a8..ceda3794d3a94 100644
--- a/test/StringProcessing/Sema/regex_literal_type_inference.swift
+++ b/test/StringProcessing/Sema/regex_literal_type_inference.swift
@@ -4,7 +4,7 @@
 let r0 = #/./#
 let _: Regex<Substring> = r0
 
-func takesRegex<Match>(_: Regex<Match>) {}
+func takesRegex<Output>(_: Regex<Output>) {}
 takesRegex(#//#) // okay
 
 let r1 = #/.(.)/#
@@ -14,7 +14,7 @@ let _: Regex<(Substring, Substring)>.Type = type(of: r1)
 
 struct S {}
 // expected-error @+2 {{cannot assign value of type 'Regex<(Substring, Substring)>' to type 'Regex<S>'}}
-// expected-note @+1 {{arguments to generic parameter 'Match' ('(Substring, Substring)' and 'S') are expected to be equal}}
+// expected-note @+1 {{arguments to generic parameter 'Output' ('(Substring, Substring)' and 'S') are expected to be equal}}
 let r2: Regex<S> = #/.(.)/#
 
 let r3 = #/(.)(.)/#