From 8ef7080c083b8fead7588cff605134c25cb371ad Mon Sep 17 00:00:00 2001
From: Som Snytt <som.snytt@gmail.com>
Date: Sat, 30 Mar 2024 13:46:56 -0700
Subject: [PATCH] Don't process ignored escapes for raw

---
 .../tools/reflect/FastStringInterpolator.scala   | 16 +++++-----------
 test/files/pos/t12976.scala                      |  6 ++++++
 2 files changed, 11 insertions(+), 11 deletions(-)
 create mode 100644 test/files/pos/t12976.scala

diff --git a/src/compiler/scala/tools/reflect/FastStringInterpolator.scala b/src/compiler/scala/tools/reflect/FastStringInterpolator.scala
index 8d19adbd3fd0..da72c2cb3e33 100644
--- a/src/compiler/scala/tools/reflect/FastStringInterpolator.scala
+++ b/src/compiler/scala/tools/reflect/FastStringInterpolator.scala
@@ -36,9 +36,9 @@ trait FastStringInterpolator extends FormatInterpolator {
         try
           parts.mapConserve {
             case lit @ Literal(Constant(stringVal: String)) =>
-              def asRaw = {
+              def asRaw = if (currentRun.sourceFeatures.unicodeEscapesRaw) stringVal else {
                 val processed = StringContext.processUnicode(stringVal)
-                if (processed != stringVal) {
+                if (processed == stringVal) stringVal else {
                   val pos = {
                     val diffindex = processed.zip(stringVal).zipWithIndex.collectFirst {
                       case ((p, o), i) if p != o => i
@@ -46,18 +46,12 @@ trait FastStringInterpolator extends FormatInterpolator {
                     lit.pos.withShift(diffindex)
                   }
                   def msg(fate: String) = s"Unicode escapes in raw interpolations are $fate; use literal characters instead"
-                  if (currentRun.sourceFeatures.unicodeEscapesRaw)
-                    stringVal
-                  else if (currentRun.isScala3) {
+                  if (currentRun.isScala3)
                     runReporting.warning(pos, msg("ignored in Scala 3 (or with -Xsource-features:unicode-escapes-raw)"), Scala3Migration, c.internal.enclosingOwner)
-                    processed
-                  }
-                  else {
+                  else
                     runReporting.deprecationWarning(pos, msg("deprecated"), "2.13.2", "", "")
-                    processed
-                  }
+                  processed
                 }
-                else stringVal
               }
               val value =
                 if (isRaw) asRaw
diff --git a/test/files/pos/t12976.scala b/test/files/pos/t12976.scala
new file mode 100644
index 000000000000..05d36de90a81
--- /dev/null
+++ b/test/files/pos/t12976.scala
@@ -0,0 +1,6 @@
+
+//> using options -Xsource:3-cross
+
+trait T {
+  def f(c: Char) = raw"\u%04X".format(c.toInt)
+}