SI-6439 Avoid spurious REPL warnings about companionship

`val m` isn't a companion of `trait m`, check the pair of
eponymous symbols are a ((class|trait), object) pair before
emitting the warning.

In order to correctly check this one a type alias is involved,
`definedSymbols` must avoid normalizing through type aliases.
AFAICT this is an improvement to the other clients of that Map,
one such power mode progression is demonstrated at the end
of the test case.

1 files changed, 22 insertions, 0 deletions

diff --git a/test/files/run/t6439.scala b/test/files/run/t6439.scala
new file mode 100644
index 0000000000..70a2dbafaf
--- /dev/null
+++ b/test/files/run/t6439.scala
@@ -0,0 +1,22 @@
+import scala.tools.partest.ReplTest
+
+object Test extends ReplTest {
+  def code = """
+class A
+object A // warn
+trait B
+object B // warn
+object C
+object Bippy
+class C // warn
+class D
+def D = 0 // no warn
+val D = 0 // no warn
+object E
+var E = 0 // no warn
+object F
+type F = Int // no warn
+:power
+intp("F") // this now works as a result of changing .typeSymbol to .typeSymbolDirect in IMain#Request#definedSymbols
+             """
+}