Reduce use of globalPrecArgText

This change is still hacky, and this shows because I can't drop the inner checks
for isInfixType.

Author: Blaisorblade

compiler/src/dotty/tools/dotc/printing/RefinedPrinter.scala

@@ -162,8 +162,8 @@ class RefinedPrinter(_ctx: Context) extends PlainPrinter(_ctx) {
        * needs to be parenthesized if it's an infix type, and vice versa. */
       val l :: r :: Nil = args
       val isRightAssoc = op.typeSymbol.name.endsWith(":")
-      val leftArg = if (isRightAssoc && isInfixType(l)) "(" ~ globalPrecArgText(l) ~ ")" else globalPrecArgText(l)
-      val rightArg = if (!isRightAssoc && isInfixType(r)) "(" ~ globalPrecArgText(r) ~ ")" else globalPrecArgText(r)
+      val leftArg = if (isRightAssoc && isInfixType(l)) changePrec(GlobalPrec) { argText(l) } else argText(l)
+      val rightArg = if (!isRightAssoc && isInfixType(r)) changePrec(GlobalPrec) { argText(r) } else argText(r)
 
       leftArg ~ " " ~ toTextLocal(op) ~ " " ~ rightArg
     }
@@ -174,7 +174,7 @@ class RefinedPrinter(_ctx: Context) extends PlainPrinter(_ctx) {
         if (tycon.isRepeatedParam) return toTextLocal(args.head) ~ "*"
         if (defn.isFunctionClass(cls)) return toTextFunction(args, cls.name.isImplicitFunction, cls.name.isErasedFunction)
         if (defn.isTupleClass(cls)) return toTextTuple(args)
-        if (isInfixType(tp)) return toTextInfixType(tycon, args)
+        if (isInfixType(tp)) return atPrec(InfixPrec) { toTextInfixType(tycon, args) }
       case EtaExpansion(tycon) =>
         return toText(tycon)
       case tp: RefinedType if defn.isFunctionType(tp) =>