Merge pull request #3878 from som-snytt/issue/8608

SI-8608 f interpolator emits constant strings

4 files changed, 34 insertions, 4 deletions

diff --git a/src/compiler/scala/tools/reflect/FormatInterpolator.scala b/src/compiler/scala/tools/reflect/FormatInterpolator.scala
index 57be1afdfe..b445f1e2bb 100644
--- a/src/compiler/scala/tools/reflect/FormatInterpolator.scala
+++ b/src/compiler/scala/tools/reflect/FormatInterpolator.scala
@@ -182,13 +182,23 @@ abstract class FormatInterpolator {
       case (part, n) => copyPart(part, n)
     }
 
-    //q"{..$evals; ${fstring.toString}.format(..$ids)}"
-    locally {
+    //q"{..$evals; new StringOps(${fstring.toString}).format(..$ids)}"
+    val format = fstring.toString
+    if (ids.isEmpty && !format.contains("%")) Literal(Constant(format))
+    else {
+      val scalaPackage = Select(Ident(nme.ROOTPKG), TermName("scala"))
+      val newStringOps = Select(
+        New(Select(Select(Select(scalaPackage,
+          TermName("collection")), TermName("immutable")), TypeName("StringOps"))),
+        termNames.CONSTRUCTOR
+      )
       val expr =
         Apply(
           Select(
-            Literal(Constant(fstring.toString)),
-            newTermName("format")),
+            Apply(
+              newStringOps,
+              List(Literal(Constant(format)))),
+            TermName("format")),
           ids.toList
         )
       val p = c.macroApplication.pos
diff --git a/test/files/run/stringinterpolation_macro-run.check b/test/files/run/stringinterpolation_macro-run.check
index ead61e76ac..c7f46bac87 100644
--- a/test/files/run/stringinterpolation_macro-run.check
+++ b/test/files/run/stringinterpolation_macro-run.check
@@ -63,5 +63,9 @@ She is 4 feet tall.
 05/26/12
 05/26/12
 %
+ mind
+------
+matter
+
 7 7 9
 7 9 9
diff --git a/test/files/run/stringinterpolation_macro-run.scala b/test/files/run/stringinterpolation_macro-run.scala
index a6def98540..e18375d521 100644
--- a/test/files/run/stringinterpolation_macro-run.scala
+++ b/test/files/run/stringinterpolation_macro-run.scala
@@ -115,6 +115,7 @@ println(f"""${"1234"}%TD""")
 
 // literals and arg indexes
 println(f"%%")
+println(f" mind%n------%nmatter%n")
 println(f"${7}%d %<d ${9}%d")
 println(f"${7}%d %2$$d ${9}%d")
 
diff --git a/test/files/run/t8608-no-format.scala b/test/files/run/t8608-no-format.scala
new file mode 100644
index 0000000000..71c369a7ea
--- /dev/null
+++ b/test/files/run/t8608-no-format.scala
@@ -0,0 +1,15 @@
+
+import scala.tools.partest.JavapTest
+
+object Test extends JavapTest {
+  def code = """
+    |f"hello, world"
+    |:javap -prv -
+  """.stripMargin
+
+  // no format
+  override def yah(res: Seq[String]) = {
+    // note: avoid the word "information"
+    res forall (!_.contains("StringOps.format"))
+  }
+}