better errors for macro applications with wrong number of arguments

The tryNamesDefaults branch of application typechecking contains the
checkNotMacro check, which errors out when we try to do named/default arguments
for macros (that's not supported yet, see SI-5920 for discussion).

Unfortunately, the check activates too early, because it turns out that
we can also enter tryNamesDefaults when the user just provides insufficient
number of arguments to a method by mistake, without expecting any default
arguments at all.

This leads to really confusing errors, which can luckily be fixed in a
very simple way by moving the checkNotMacro check down the happy path
of named/default typechecking.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
index 3a85d16f55..d4756f0af3 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
@@ -3387,7 +3387,6 @@ trait Typers extends Adaptations with Tags with TypersTracking with PatternTyper
               // defaults are needed. they are added to the argument list in named style as
               // calls to the default getters. Example:
               //  foo[Int](a)()  ==>  foo[Int](a)(b = foo$qual.foo$default$2[Int](a))
-              checkNotMacro()
 
               // SI-8111 transformNamedApplication eagerly shuffles around the application to preserve
               //         evaluation order. During this process, it calls `changeOwner` on symbols that
@@ -3434,6 +3433,7 @@ trait Typers extends Adaptations with Tags with TypersTracking with PatternTyper
                   duplErrTree
                 } else if (lencmp2 == 0) {
                   // useful when a default doesn't match parameter type, e.g. def f[T](x:T="a"); f[Int]()
+                  checkNotMacro()
                   context.diagUsedDefaults = true
                   doTypedApply(tree, if (blockIsEmpty) fun else fun1, allArgs, mode, pt)
                 } else {