SI-8092 More verify for f-interpolator

Attempt to verify the nooks and crannies of the format string.

Allows all syntax in the javadoc, including arg indexes. If the
specifier after an arg has an index that doesn't refer to the arg,
a warning is issued and the missing `%s` is prepended (just as
for a part with a leading `%n`).

Other enhancements include detecting that a `Formattable` wasn't
supplied to `%#s`.

Error messages attempt to be pithy but descriptive.

1 files changed, 42 insertions, 0 deletions

diff --git a/test/files/neg/stringinterpolation_macro-neg.scala b/test/files/neg/stringinterpolation_macro-neg.scala
index ac9d97d678..c5ae708f21 100644
--- a/test/files/neg/stringinterpolation_macro-neg.scala
+++ b/test/files/neg/stringinterpolation_macro-neg.scala
@@ -3,6 +3,11 @@ object Test extends App {
   val d = 8
   val b = false
   val f = 3.14159
+  val c = 'c'
+  val t = new java.util.Date
+  val x = new java.util.Formattable {
+    def formatTo(ff: java.util.Formatter, g: Int, w: Int, p: Int): Unit = ff format "xxx"
+  }
 
   // 1) number of arguments
   new StringContext().f()
@@ -28,4 +33,41 @@ object Test extends App {
   }
 
   f"$s%i"
+
+  // 3) flag mismatches
+  f"$s%+ 0,(s"
+  f"$c%#+ 0,(c"
+  f"$d%#d"
+  f"$d%,x"
+  f"$d%+ (x"
+  f"$f%,(a"
+  f"$t%#+ 0,(tT"
+
+  // 4) bad precisions
+  f"$c%.2c"
+  f"$d%.2d"
+  f"%.2%"
+  f"%.2n"
+  f"$f%.2a"
+  f"$t%.2tT"
+
+  // 5) bad indexes
+  f"%<s"
+  f"%<c"
+  f"%<tT"
+  f"${8}%d ${9}%d%3$$d"
+  f"${8}%d ${9}%d%0$$d"
+
+  // warnings
+  f"${8}%d ${9}%1$$d"
+  f"$s%s $s%s %1$$<s"
+  f"$s%s $s%1$$s"
+
+  // 6) bad arg types
+  f"$s%#s"
+
+  // 7) misunderstood conversions
+  f"$t%tG"
+  f"$t%t"
+  f"$s%10.5"
 }