SI-9127 Xlint doesn't think spaces are significant

For purposes of warning about missing interpolators,
such as `"$greeting"` when the intended code was `s"$greeting"`,
spaces are no longer significant.

The heuristic was previously intended to allow compileresque
strings, where the dollar sign is a common prefix.

Currently, the Xlint warning can be selectively disabled.

1 files changed, 4 insertions, 7 deletions

diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
index 3a85d16f55..8efef8b4aa 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
@@ -5200,13 +5200,10 @@ trait Typers extends Adaptations with Tags with TypersTracking with PatternTyper
           def suspiciousExpr                = InterpolatorCodeRegex findFirstIn s
           def suspiciousIdents              = InterpolatorIdentRegex findAllIn s map (s => suspiciousSym(s drop 1))
 
-          // heuristics - no warning on e.g. a string with only "$asInstanceOf"
-          if (s contains ' ') (
-            if (suspiciousExpr.nonEmpty)
-              warn("detected an interpolated expression") // "${...}"
-            else
-              suspiciousIdents find isPlausible foreach (sym => warn(s"detected interpolated identifier `$$${sym.name}`")) // "$id"
-          )
+          if (suspiciousExpr.nonEmpty)
+            warn("detected an interpolated expression") // "${...}"
+          else
+            suspiciousIdents find isPlausible foreach (sym => warn(s"detected interpolated identifier `$$${sym.name}`")) // "$id"
         }
         lit match {
           case Literal(Constant(s: String)) if !isRecognizablyNotForInterpolation => maybeWarn(s)