SI-6539 Annotation for methods unfit for post-typer ASTs

Motivated by the `.value` method in the SBT task-syntax branch,
which should only be called within the context of the argument
to a setting initialization macro.

The facility is akin to a fatal deprecation.

2 files changed, 16 insertions, 0 deletions

diff --git a/test/files/neg/t6539/Macro_1.scala b/test/files/neg/t6539/Macro_1.scala
new file mode 100644
index 0000000000..69bd53fe07
--- /dev/null
+++ b/test/files/neg/t6539/Macro_1.scala
@@ -0,0 +1,10 @@
+import language.experimental.macros
+import reflect.macros.Context
+
+object M {
+	def m(a: Any, b: Any): Any = macro mImpl
+	def mImpl(c: Context)(a: c.Expr[Any], b: c.Expr[Any]) = a
+
+  @reflect.macros.compileTimeOnly("cto may only be used as an argument to m")
+	def cto = 0
+}
diff --git a/test/files/neg/t6539/Test_2.scala b/test/files/neg/t6539/Test_2.scala
new file mode 100644
index 0000000000..1569c79788
--- /dev/null
+++ b/test/files/neg/t6539/Test_2.scala
@@ -0,0 +1,6 @@
+object Test {
+	M.cto // error
+	M.m(M.cto, ()) // error
+	M.m((), M.cto) // okay
+	M.cto // error
+}
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