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, 66 insertions, 0 deletions

diff --git a/test/files/run/t6439.check b/test/files/run/t6439.check
new file mode 100644
index 0000000000..178ea739f5
--- /dev/null
+++ b/test/files/run/t6439.check
@@ -0,0 +1,66 @@
+Type in expressions to have them evaluated.
+Type :help for more information.
+
+scala> 
+
+scala> class A
+defined class A
+
+scala> object A // warn
+defined module A
+warning: previously defined class A is not a companion to object A.
+Companions must be defined together; you may wish to use :paste mode for this.
+
+scala> trait B
+defined trait B
+
+scala> object B // warn
+defined module B
+warning: previously defined trait B is not a companion to object B.
+Companions must be defined together; you may wish to use :paste mode for this.
+
+scala> object C
+defined module C
+
+scala> object Bippy
+defined module Bippy
+
+scala> class C // warn
+defined class C
+warning: previously defined object C is not a companion to class C.
+Companions must be defined together; you may wish to use :paste mode for this.
+
+scala> class D
+defined class D
+
+scala> def D = 0 // no warn
+D: Int
+
+scala> val D = 0 // no warn
+D: Int = 0
+
+scala> object E
+defined module E
+
+scala> var E = 0 // no warn
+E: Int = 0
+
+scala> object F
+defined module F
+
+scala> type F = Int // no warn
+defined type alias F
+
+scala> :power
+** Power User mode enabled - BEEP WHIR GYVE **
+** :phase has been set to 'typer'.          **
+** scala.tools.nsc._ has been imported      **
+** global._, definitions._ also imported    **
+** Try  :help, :vals, power.<tab>           **
+
+scala> intp("F") // this now works as a result of changing .typeSymbol to .typeSymbolDirect in IMain#Request#definedSymbols
+res0: $r.intp.global.Symbol = type F
+
+scala> 
+
+scala>