diff --git a/tests/neg/f-interpolator-neg.check b/tests/neg/f-interpolator-neg.check
index ea8df052589e..fe82f197ad56 100644
--- a/tests/neg/f-interpolator-neg.check
+++ b/tests/neg/f-interpolator-neg.check
@@ -1,200 +1,200 @@
--- Error: tests/neg/f-interpolator-neg.scala:4:4 -----------------------------------------------------------------------
-4 |    new StringContext().f() // error
-  |    ^^^^^^^^^^^^^^^^^^^^^
-  |    there are no parts
--- Error: tests/neg/f-interpolator-neg.scala:5:4 -----------------------------------------------------------------------
-5 |    new StringContext("", " is ", "%2d years old").f(s) // error
-  |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-  |    too few arguments for interpolated string
--- Error: tests/neg/f-interpolator-neg.scala:6:4 -----------------------------------------------------------------------
-6 |    new StringContext("", " is ", "%2d years old").f(s, d, d) // error
-  |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-  |    too many arguments for interpolated string
--- Error: tests/neg/f-interpolator-neg.scala:7:4 -----------------------------------------------------------------------
-7 |    new StringContext("", "").f() // error
-  |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^
-  |    too few arguments for interpolated string
--- Error: tests/neg/f-interpolator-neg.scala:11:7 ----------------------------------------------------------------------
-11 |    f"$s%b" // error
-   |       ^
-   |       Found: (s : String), Required: Boolean, Null
--- Error: tests/neg/f-interpolator-neg.scala:12:7 ----------------------------------------------------------------------
-12 |    f"$s%c" // error
-   |       ^
-   |       Found: (s : String), Required: Char, Byte, Short, Int
--- Error: tests/neg/f-interpolator-neg.scala:13:7 ----------------------------------------------------------------------
-13 |    f"$f%c" // error
-   |       ^
-   |       Found: (f : Double), Required: Char, Byte, Short, Int
--- Error: tests/neg/f-interpolator-neg.scala:14:7 ----------------------------------------------------------------------
-14 |    f"$s%x" // error
-   |       ^
-   |       Found: (s : String), Required: Int, Long, Byte, Short, BigInt
--- Error: tests/neg/f-interpolator-neg.scala:15:7 ----------------------------------------------------------------------
-15 |    f"$b%d" // error
-   |       ^
-   |       Found: (b : Boolean), Required: Int, Long, Byte, Short, BigInt
--- Error: tests/neg/f-interpolator-neg.scala:16:7 ----------------------------------------------------------------------
-16 |    f"$s%d" // error
-   |       ^
-   |       Found: (s : String), Required: Int, Long, Byte, Short, BigInt
--- Error: tests/neg/f-interpolator-neg.scala:17:7 ----------------------------------------------------------------------
-17 |    f"$f%o" // error
-   |       ^
-   |       Found: (f : Double), Required: Int, Long, Byte, Short, BigInt
--- Error: tests/neg/f-interpolator-neg.scala:18:7 ----------------------------------------------------------------------
-18 |    f"$s%e" // error
-   |       ^
-   |       Found: (s : String), Required: Double, Float, BigDecimal
--- Error: tests/neg/f-interpolator-neg.scala:19:7 ----------------------------------------------------------------------
-19 |    f"$b%f" // error
-   |       ^
-   |       Found: (b : Boolean), Required: Double, Float, BigDecimal
--- Error: tests/neg/f-interpolator-neg.scala:20:9 ----------------------------------------------------------------------
-20 |    f"$s%i" // error
-   |         ^
-   |         illegal conversion character 'i'
--- Error: tests/neg/f-interpolator-neg.scala:24:9 ----------------------------------------------------------------------
-24 |    f"$s%+ 0,(s" // error
-   |         ^^^^^
-   |         Illegal flag '+'
--- Error: tests/neg/f-interpolator-neg.scala:25:9 ----------------------------------------------------------------------
-25 |    f"$c%#+ 0,(c" // error
-   |         ^^^^^^
-   |         Only '-' allowed for c conversion
--- Error: tests/neg/f-interpolator-neg.scala:26:9 ----------------------------------------------------------------------
-26 |    f"$d%#d" // error
-   |         ^
-   |         # not allowed for d conversion
--- Error: tests/neg/f-interpolator-neg.scala:27:9 ----------------------------------------------------------------------
-27 |    f"$d%,x" // error
-   |         ^
-   |         ',' only allowed for d conversion of integral types
--- Error: tests/neg/f-interpolator-neg.scala:28:9 ----------------------------------------------------------------------
-28 |    f"$d%+ (x" // error
-   |         ^^^
-   |         only use '+' for BigInt conversions to o, x, X
--- Error: tests/neg/f-interpolator-neg.scala:29:9 ----------------------------------------------------------------------
-29 |    f"$f%,(a" // error
-   |         ^^
-   |         ',' not allowed for a, A
--- Error: tests/neg/f-interpolator-neg.scala:30:9 ----------------------------------------------------------------------
-30 |    f"$t%#+ 0,(tT" // error
-   |         ^^^^^^
-   |         Only '-' allowed for date/time conversions
--- Error: tests/neg/f-interpolator-neg.scala:31:7 ----------------------------------------------------------------------
-31 |    f"%-#+ 0,(n" // error
-   |       ^^^^^^^
-   |       flags not allowed
--- Error: tests/neg/f-interpolator-neg.scala:32:7 ----------------------------------------------------------------------
-32 |    f"%#+ 0,(%" // error
-   |       ^^^^^^
-   |       Illegal flag '#'
--- Error: tests/neg/f-interpolator-neg.scala:36:9 ----------------------------------------------------------------------
-36 |    f"$c%.2c" // error
-   |         ^^
-   |         precision not allowed
--- Error: tests/neg/f-interpolator-neg.scala:37:9 ----------------------------------------------------------------------
-37 |    f"$d%.2d" // error
-   |         ^^
-   |         precision not allowed
--- Error: tests/neg/f-interpolator-neg.scala:38:7 ----------------------------------------------------------------------
-38 |    f"%.2%" // error
-   |       ^^
-   |       precision not allowed
--- Error: tests/neg/f-interpolator-neg.scala:39:7 ----------------------------------------------------------------------
-39 |    f"%.2n" // error
-   |       ^^
-   |       precision not allowed
--- Error: tests/neg/f-interpolator-neg.scala:40:9 ----------------------------------------------------------------------
-40 |    f"$f%.2a" // error
-   |         ^^
-   |         precision not allowed
--- Error: tests/neg/f-interpolator-neg.scala:41:9 ----------------------------------------------------------------------
-41 |    f"$t%.2tT" // error
-   |         ^^
-   |         precision not allowed
--- Error: tests/neg/f-interpolator-neg.scala:45:7 ----------------------------------------------------------------------
-45 |    f"%<s" // error
-   |       ^
-   |       No last arg
--- Error: tests/neg/f-interpolator-neg.scala:46:7 ----------------------------------------------------------------------
-46 |    f"%<c" // error
-   |       ^
-   |       No last arg
--- Error: tests/neg/f-interpolator-neg.scala:47:7 ----------------------------------------------------------------------
-47 |    f"%<tT" // error
-   |       ^
-   |       No last arg
--- Error: tests/neg/f-interpolator-neg.scala:48:21 ---------------------------------------------------------------------
-48 |    f"${8}%d ${9}%d %3$$d" // error
-   |                     ^
-   |                     Argument index out of range
--- Error: tests/neg/f-interpolator-neg.scala:49:20 ---------------------------------------------------------------------
-49 |    f"${8}%d ${9}%d%0$$d" // error
-   |                    ^
-   |                    Argument index out of range
--- Warning: tests/neg/f-interpolator-neg.scala:54:17 -------------------------------------------------------------------
-54 |    f"$s%s $s%s %1$$<s"
+-- Error: tests/neg/f-interpolator-neg.scala:4:12 ----------------------------------------------------------------------
+4 |    val _ = new StringContext().f() // error
+  |            ^^^^^^^^^^^^^^^^^^^^^
+  |            there are no parts
+-- Error: tests/neg/f-interpolator-neg.scala:5:12 ----------------------------------------------------------------------
+5 |    val _ = new StringContext("", " is ", "%2d years old").f(s) // error
+  |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+  |            too few arguments for interpolated string
+-- Error: tests/neg/f-interpolator-neg.scala:6:12 ----------------------------------------------------------------------
+6 |    val _ = new StringContext("", " is ", "%2d years old").f(s, d, d) // error
+  |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+  |            too many arguments for interpolated string
+-- Error: tests/neg/f-interpolator-neg.scala:7:12 ----------------------------------------------------------------------
+7 |    val _ = new StringContext("", "").f() // error
+  |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+  |            too few arguments for interpolated string
+-- Error: tests/neg/f-interpolator-neg.scala:11:15 ---------------------------------------------------------------------
+11 |    val _ = f"$s%b" // error
+   |               ^
+   |               Found: (s : String), Required: Boolean, Null
+-- Error: tests/neg/f-interpolator-neg.scala:12:15 ---------------------------------------------------------------------
+12 |    val _ = f"$s%c" // error
+   |               ^
+   |               Found: (s : String), Required: Char, Byte, Short, Int
+-- Error: tests/neg/f-interpolator-neg.scala:13:15 ---------------------------------------------------------------------
+13 |    val _ = f"$f%c" // error
+   |               ^
+   |               Found: (f : Double), Required: Char, Byte, Short, Int
+-- Error: tests/neg/f-interpolator-neg.scala:14:15 ---------------------------------------------------------------------
+14 |    val _ = f"$s%x" // error
+   |               ^
+   |               Found: (s : String), Required: Int, Long, Byte, Short, BigInt
+-- Error: tests/neg/f-interpolator-neg.scala:15:15 ---------------------------------------------------------------------
+15 |    val _ = f"$b%d" // error
+   |               ^
+   |               Found: (b : Boolean), Required: Int, Long, Byte, Short, BigInt
+-- Error: tests/neg/f-interpolator-neg.scala:16:15 ---------------------------------------------------------------------
+16 |    val _ = f"$s%d" // error
+   |               ^
+   |               Found: (s : String), Required: Int, Long, Byte, Short, BigInt
+-- Error: tests/neg/f-interpolator-neg.scala:17:15 ---------------------------------------------------------------------
+17 |    val _ = f"$f%o" // error
+   |               ^
+   |               Found: (f : Double), Required: Int, Long, Byte, Short, BigInt
+-- Error: tests/neg/f-interpolator-neg.scala:18:15 ---------------------------------------------------------------------
+18 |    val _ = f"$s%e" // error
+   |               ^
+   |               Found: (s : String), Required: Double, Float, BigDecimal
+-- Error: tests/neg/f-interpolator-neg.scala:19:17 ---------------------------------------------------------------------
+19 |    val _ = f"$b%val _ = f" // error
+   |                 ^
+   |                 illegal conversion character 'v'
+-- Error: tests/neg/f-interpolator-neg.scala:20:17 ---------------------------------------------------------------------
+20 |    val _ = f"$s%i" // error
+   |                 ^
+   |                 illegal conversion character 'i'
+-- Error: tests/neg/f-interpolator-neg.scala:24:17 ---------------------------------------------------------------------
+24 |    val _ = f"$s%+ 0,(s" // error
+   |                 ^^^^^
+   |                 Illegal flag '+'
+-- Error: tests/neg/f-interpolator-neg.scala:25:17 ---------------------------------------------------------------------
+25 |    val _ = f"$c%#+ 0,(c" // error
+   |                 ^^^^^^
+   |                 Only '-' allowed for c conversion
+-- Error: tests/neg/f-interpolator-neg.scala:26:17 ---------------------------------------------------------------------
+26 |    val _ = f"$d%#d" // error
+   |                 ^
+   |                 # not allowed for d conversion
+-- Error: tests/neg/f-interpolator-neg.scala:27:17 ---------------------------------------------------------------------
+27 |    val _ = f"$d%,x" // error
    |                 ^
-   |                 Argument index ignored if '<' flag is present
--- Error: tests/neg/f-interpolator-neg.scala:59:7 ----------------------------------------------------------------------
-59 |    f"$s%#s" // error
-   |       ^
-   |       Found: (s : String), Required: java.util.Formattable
--- Error: tests/neg/f-interpolator-neg.scala:63:10 ---------------------------------------------------------------------
-63 |    f"$t%tG" // error
-   |          ^
-   |          'G' doesn't seem to be a date or time conversion
--- Error: tests/neg/f-interpolator-neg.scala:64:9 ----------------------------------------------------------------------
-64 |    f"$t%t" // error
-   |         ^
-   |         Date/time conversion must have two characters
--- Error: tests/neg/f-interpolator-neg.scala:65:8 ----------------------------------------------------------------------
-65 |    f"$s%10.5" // error
-   |        ^^^^^
-   |        Missing conversion operator in '%10.5'; use %% for literal %, %n for newline
--- Error: tests/neg/f-interpolator-neg.scala:69:29 ---------------------------------------------------------------------
-69 |    f"${d}random-leading-junk%d" // error
-   |                             ^^
-   |                             conversions must follow a splice; use %% for literal %, %n for newline
--- Error: tests/neg/f-interpolator-neg.scala:71:7 ----------------------------------------------------------------------
-71 |    f"%1$$d" // error
-   |       ^
-   |       Argument index out of range
--- Error: tests/neg/f-interpolator-neg.scala:72:23 ---------------------------------------------------------------------
-72 |    f"blablablabla %% %.2d" // error
-   |                       ^^
-   |                       precision not allowed
--- Error: tests/neg/f-interpolator-neg.scala:73:19 ---------------------------------------------------------------------
-73 |    f"blablablabla %.2b %%" // error
-   |                   ^^^^
-   |                   conversions must follow a splice; use %% for literal %, %n for newline
--- Error: tests/neg/f-interpolator-neg.scala:75:17 ---------------------------------------------------------------------
-75 |    f"ana${3}%.2f%2${true}%bb" // error
+   |                 ',' only allowed for d conversion of integral types
+-- Error: tests/neg/f-interpolator-neg.scala:28:17 ---------------------------------------------------------------------
+28 |    val _ = f"$d%+ (x" // error
+   |                 ^^^
+   |                 only use '+' for BigInt conversions to o, x, X
+-- Error: tests/neg/f-interpolator-neg.scala:29:17 ---------------------------------------------------------------------
+29 |    val _ = f"$f%,(a" // error
    |                 ^^
-   |                 Missing conversion operator in '%2'; use %% for literal %, %n for newline
--- Error: tests/neg/f-interpolator-neg.scala:78:7 ----------------------------------------------------------------------
-78 |    f"b%c.%2ii%iin" // error // error // error
-   |       ^^
-   |       conversions must follow a splice; use %% for literal %, %n for newline
--- Error: tests/neg/f-interpolator-neg.scala:78:12 ---------------------------------------------------------------------
-78 |    f"b%c.%2ii%iin" // error // error // error
-   |            ^
-   |            illegal conversion character 'i'
--- Error: tests/neg/f-interpolator-neg.scala:78:15 ---------------------------------------------------------------------
-78 |    f"b%c.%2ii%iin" // error // error // error
+   |                 ',' not allowed for a, A
+-- Error: tests/neg/f-interpolator-neg.scala:30:17 ---------------------------------------------------------------------
+30 |    val _ = f"$t%#+ 0,(tT" // error
+   |                 ^^^^^^
+   |                 Only '-' allowed for date/time conversions
+-- Error: tests/neg/f-interpolator-neg.scala:31:15 ---------------------------------------------------------------------
+31 |    val _ = f"%-#+ 0,(n" // error
+   |               ^^^^^^^
+   |               flags not allowed
+-- Error: tests/neg/f-interpolator-neg.scala:32:15 ---------------------------------------------------------------------
+32 |    val _ = f"%#+ 0,(%" // error
+   |               ^^^^^^
+   |               Illegal flag '#'
+-- Error: tests/neg/f-interpolator-neg.scala:36:17 ---------------------------------------------------------------------
+36 |    val _ = f"$c%.2c" // error
+   |                 ^^
+   |                 precision not allowed
+-- Error: tests/neg/f-interpolator-neg.scala:37:17 ---------------------------------------------------------------------
+37 |    val _ = f"$d%.2d" // error
+   |                 ^^
+   |                 precision not allowed
+-- Error: tests/neg/f-interpolator-neg.scala:38:15 ---------------------------------------------------------------------
+38 |    val _ = f"%.2%" // error
+   |               ^^
+   |               precision not allowed
+-- Error: tests/neg/f-interpolator-neg.scala:39:15 ---------------------------------------------------------------------
+39 |    val _ = f"%.2n" // error
+   |               ^^
+   |               precision not allowed
+-- Error: tests/neg/f-interpolator-neg.scala:40:17 ---------------------------------------------------------------------
+40 |    val _ = f"$f%.2a" // error
+   |                 ^^
+   |                 precision not allowed
+-- Error: tests/neg/f-interpolator-neg.scala:41:17 ---------------------------------------------------------------------
+41 |    val _ = f"$t%.2tT" // error
+   |                 ^^
+   |                 precision not allowed
+-- Error: tests/neg/f-interpolator-neg.scala:45:15 ---------------------------------------------------------------------
+45 |    val _ = f"%<s" // error
+   |               ^
+   |               No last arg
+-- Error: tests/neg/f-interpolator-neg.scala:46:15 ---------------------------------------------------------------------
+46 |    val _ = f"%<c" // error
    |               ^
-   |               illegal conversion character 'i'
--- Error: tests/neg/f-interpolator-neg.scala:79:10 ---------------------------------------------------------------------
-79 |    f"b}22%2.c<{%{"  // error // error
-   |          ^^
-   |          Missing conversion operator in '%2'; use %% for literal %, %n for newline
--- Error: tests/neg/f-interpolator-neg.scala:79:16 ---------------------------------------------------------------------
-79 |    f"b}22%2.c<{%{"  // error // error
-   |                ^
-   |                Missing conversion operator in '%'; use %% for literal %, %n for newline
--- Error: tests/neg/f-interpolator-neg.scala:80:19 ---------------------------------------------------------------------
-80 |    f"%%bci.2${'i'}%..2c2" // error
-   |                   ^
-   |                   Missing conversion operator in '%'; use %% for literal %, %n for newline
+   |               No last arg
+-- Error: tests/neg/f-interpolator-neg.scala:47:15 ---------------------------------------------------------------------
+47 |    val _ = f"%<tT" // error
+   |               ^
+   |               No last arg
+-- Error: tests/neg/f-interpolator-neg.scala:48:29 ---------------------------------------------------------------------
+48 |    val _ = f"${8}%d ${9}%d %3$$d" // error
+   |                             ^
+   |                             Argument index out of range
+-- Error: tests/neg/f-interpolator-neg.scala:49:28 ---------------------------------------------------------------------
+49 |    val _ = f"${8}%d ${9}%d%0$$d" // error
+   |                            ^
+   |                            Argument index out of range
+-- Warning: tests/neg/f-interpolator-neg.scala:54:25 -------------------------------------------------------------------
+54 |    val _ = f"$s%s $s%s %1$$<s"
+   |                         ^
+   |                         Argument index ignored if '<' flag is present
+-- Error: tests/neg/f-interpolator-neg.scala:59:15 ---------------------------------------------------------------------
+59 |    val _ = f"$s%#s" // error
+   |               ^
+   |               Found: (s : String), Required: java.util.Formattable
+-- Error: tests/neg/f-interpolator-neg.scala:63:18 ---------------------------------------------------------------------
+63 |    val _ = f"$t%tG" // error
+   |                  ^
+   |                  'G' doesn't seem to be a date or time conversion
+-- Error: tests/neg/f-interpolator-neg.scala:64:17 ---------------------------------------------------------------------
+64 |    val _ = f"$t%t" // error
+   |                 ^
+   |                 Date/time conversion must have two characters
+-- Error: tests/neg/f-interpolator-neg.scala:65:16 ---------------------------------------------------------------------
+65 |    val _ = f"$s%10.5" // error
+   |                ^^^^^
+   |                Missing conversion operator in '%10.5'; use %% for literal %, %n for newline
+-- Error: tests/neg/f-interpolator-neg.scala:69:37 ---------------------------------------------------------------------
+69 |    val _ = f"${d}random-leading-junk%d" // error
+   |                                     ^^
+   |                                     conversions must follow a splice; use %% for literal %, %n for newline
+-- Error: tests/neg/f-interpolator-neg.scala:71:15 ---------------------------------------------------------------------
+71 |    val _ = f"%1$$d" // error
+   |               ^
+   |               Argument index out of range
+-- Error: tests/neg/f-interpolator-neg.scala:72:31 ---------------------------------------------------------------------
+72 |    val _ = f"blablablabla %% %.2d" // error
+   |                               ^^
+   |                               precision not allowed
+-- Error: tests/neg/f-interpolator-neg.scala:73:27 ---------------------------------------------------------------------
+73 |    val _ = f"blablablabla %.2b %%" // error
+   |                           ^^^^
+   |                           conversions must follow a splice; use %% for literal %, %n for newline
+-- Error: tests/neg/f-interpolator-neg.scala:75:25 ---------------------------------------------------------------------
+75 |    val _ = f"ana${3}%.2f%2${true}%bb" // error
+   |                         ^^
+   |                         Missing conversion operator in '%2'; use %% for literal %, %n for newline
+-- Error: tests/neg/f-interpolator-neg.scala:78:15 ---------------------------------------------------------------------
+78 |    val _ = f"b%c.%2ii%iin" // error // error // error
+   |               ^^
+   |               conversions must follow a splice; use %% for literal %, %n for newline
+-- Error: tests/neg/f-interpolator-neg.scala:78:20 ---------------------------------------------------------------------
+78 |    val _ = f"b%c.%2ii%iin" // error // error // error
+   |                    ^
+   |                    illegal conversion character 'i'
+-- Error: tests/neg/f-interpolator-neg.scala:78:23 ---------------------------------------------------------------------
+78 |    val _ = f"b%c.%2ii%iin" // error // error // error
+   |                       ^
+   |                       illegal conversion character 'i'
+-- Error: tests/neg/f-interpolator-neg.scala:79:18 ---------------------------------------------------------------------
+79 |    val _ = f"b}22%2.c<{%{"  // error // error
+   |                  ^^
+   |                  Missing conversion operator in '%2'; use %% for literal %, %n for newline
+-- Error: tests/neg/f-interpolator-neg.scala:79:24 ---------------------------------------------------------------------
+79 |    val _ = f"b}22%2.c<{%{"  // error // error
+   |                        ^
+   |                        Missing conversion operator in '%'; use %% for literal %, %n for newline
+-- Error: tests/neg/f-interpolator-neg.scala:80:27 ---------------------------------------------------------------------
+80 |    val _ = f"%%bci.2${'i'}%..2c2" // error
+   |                           ^
+   |                           Missing conversion operator in '%'; use %% for literal %, %n for newline
diff --git a/tests/neg/f-interpolator-neg.scala b/tests/neg/f-interpolator-neg.scala
index d5c49d5a8111..294ed40f2a02 100644
--- a/tests/neg/f-interpolator-neg.scala
+++ b/tests/neg/f-interpolator-neg.scala
@@ -1,83 +1,83 @@
 object Test {
 
   def numberArgumentsTests(s : String, d : Int) = {
-    new StringContext().f() // error
-    new StringContext("", " is ", "%2d years old").f(s) // error
-    new StringContext("", " is ", "%2d years old").f(s, d, d) // error
-    new StringContext("", "").f() // error
+    val _ = new StringContext().f() // error
+    val _ = new StringContext("", " is ", "%2d years old").f(s) // error
+    val _ = new StringContext("", " is ", "%2d years old").f(s, d, d) // error
+    val _ = new StringContext("", "").f() // error
   }
 
   def interpolationMismatches(s : String, f : Double, b : Boolean) = {
-    f"$s%b" // error
-    f"$s%c" // error
-    f"$f%c" // error
-    f"$s%x" // error
-    f"$b%d" // error
-    f"$s%d" // error
-    f"$f%o" // error
-    f"$s%e" // error
-    f"$b%f" // error
-    f"$s%i" // error
+    val _ = f"$s%b" // error
+    val _ = f"$s%c" // error
+    val _ = f"$f%c" // error
+    val _ = f"$s%x" // error
+    val _ = f"$b%d" // error
+    val _ = f"$s%d" // error
+    val _ = f"$f%o" // error
+    val _ = f"$s%e" // error
+    val _ = f"$b%val _ = f" // error
+    val _ = f"$s%i" // error
   }
 
   def flagMismatches(s : String, c : Char, d : Int, f : Double, t : java.util.Date) = {
-    f"$s%+ 0,(s" // error
-    f"$c%#+ 0,(c" // error
-    f"$d%#d" // error
-    f"$d%,x" // error
-    f"$d%+ (x" // error
-    f"$f%,(a" // error
-    f"$t%#+ 0,(tT" // error
-    f"%-#+ 0,(n" // error
-    f"%#+ 0,(%" // error
+    val _ = f"$s%+ 0,(s" // error
+    val _ = f"$c%#+ 0,(c" // error
+    val _ = f"$d%#d" // error
+    val _ = f"$d%,x" // error
+    val _ = f"$d%+ (x" // error
+    val _ = f"$f%,(a" // error
+    val _ = f"$t%#+ 0,(tT" // error
+    val _ = f"%-#+ 0,(n" // error
+    val _ = f"%#+ 0,(%" // error
   }
 
   def badPrecisions(c : Char, d : Int, f : Double, t : java.util.Date) = {
-    f"$c%.2c" // error
-    f"$d%.2d" // error
-    f"%.2%" // error
-    f"%.2n" // error
-    f"$f%.2a" // error
-    f"$t%.2tT" // error
+    val _ = f"$c%.2c" // error
+    val _ = f"$d%.2d" // error
+    val _ = f"%.2%" // error
+    val _ = f"%.2n" // error
+    val _ = f"$f%.2a" // error
+    val _ = f"$t%.2tT" // error
   }
 
   def badIndexes() = {
-    f"%<s" // error
-    f"%<c" // error
-    f"%<tT" // error
-    f"${8}%d ${9}%d %3$$d" // error
-    f"${8}%d ${9}%d%0$$d" // error
+    val _ = f"%<s" // error
+    val _ = f"%<c" // error
+    val _ = f"%<tT" // error
+    val _ = f"${8}%d ${9}%d %3$$d" // error
+    val _ = f"${8}%d ${9}%d%0$$d" // error
   }
 
   def warnings(s : String) = {
-    f"${8}%d ${9}%1$$d"
-    f"$s%s $s%s %1$$<s"
-    f"$s%s $s%1$$s"
+    val _ = f"${8}%d ${9}%1$$d"
+    val _ = f"$s%s $s%s %1$$<s"
+    val _ = f"$s%s $s%1$$s"
   }
 
   def badArgTypes(s : String) = {
-    f"$s%#s" // error
+    val _ = f"$s%#s" // error
   }
 
   def misunderstoodConversions(t : java.util.Date, s : String) = {
-    f"$t%tG" // error
-    f"$t%t" // error
-    f"$s%10.5" // error
+    val _ = f"$t%tG" // error
+    val _ = f"$t%t" // error
+    val _ = f"$s%10.5" // error
   }
 
   def otherBrainFailures(d : Int) = {
-    f"${d}random-leading-junk%d" // error
-    f"%1$$n"
-    f"%1$$d" // error
-    f"blablablabla %% %.2d" // error
-    f"blablablabla %.2b %%" // error
+    val _ = f"${d}random-leading-junk%d" // error
+    val _ = f"%1$$n"
+    val _ = f"%1$$d" // error
+    val _ = f"blablablabla %% %.2d" // error
+    val _ = f"blablablabla %.2b %%" // error
 
-    f"ana${3}%.2f%2${true}%bb" // error
-    f"ac{2c{2{c.ca "
+    val _ = f"ana${3}%.2f%2${true}%bb" // error
+    val _ = f"ac{2c{2{c.ca "
 
-    f"b%c.%2ii%iin" // error // error // error
-    f"b}22%2.c<{%{"  // error // error
-    f"%%bci.2${'i'}%..2c2" // error
+    val _ = f"b%c.%2ii%iin" // error // error // error
+    val _ = f"b}22%2.c<{%{"  // error // error
+    val _ = f"%%bci.2${'i'}%..2c2" // error
   }
 
 }