Address notes from @milseman

Author: natecook1000

Sources/_StringProcessing/ByteCodeGen.swift

@@ -296,8 +296,8 @@ fileprivate extension Compiler.ByteCodeGen {
       save(restoringAt: success)
       save(restoringAt: intercept)
       <sub-pattern>    // failure restores at intercept
-      clearThrough(intercept) // remove intercept and any leftovers from <sub-pattern>
-      fail             // ->success
+      clearThrough(intercept)       // remove intercept and any leftovers from <sub-pattern>
+     fail(preservingCaptures: true) // ->success
     intercept:
       clearSavePoint   // remove success
       fail             // propagate failure
@@ -370,8 +370,8 @@ fileprivate extension Compiler.ByteCodeGen {
       save(continuingAt: success)
       save(restoringAt: intercept)
       <sub-pattern>    // failure restores at intercept
-      clearThrough(intercept) // remove intercept and any leftovers from <sub-pattern>
-      fail             // ->success
+      clearThrough(intercept)        // remove intercept and any leftovers from <sub-pattern>
+      fail(preservingCaptures: true) // ->success
     intercept:
       clearSavePoint   // remove success
       fail             // propagate failure

Sources/_StringProcessing/Engine/Processor.swift

@@ -354,13 +354,7 @@ extension Processor {
     registers.ints = intRegisters
     registers.positions = posRegisters
 
-    if preservingCaptures {
-      for i in capEnds.indices {
-        if storedCaptures[i].range == nil {
-          storedCaptures[i].currentCaptureBegin = capEnds[i].currentCaptureBegin
-        }
-      }
-    } else {
+    if !preservingCaptures {
       // Reset all capture information
       storedCaptures = capEnds
     }