fixes nim-lang/nimsuggest#103 con dot exprs (#16657)

- con calls for dot exprs now returns results
- discovered an issue with dot expr results -- documented

compiler/suggest.nim

@@ -298,6 +298,7 @@ proc suggestObject(c: PContext, n, f: PNode; info: TLineInfo, outputs: var Sugge
 proc nameFits(c: PContext, s: PSym, n: PNode): bool =
   var op = if n.kind in nkCallKinds: n[0] else: n
   if op.kind in {nkOpenSymChoice, nkClosedSymChoice}: op = op[0]
+  if op.kind == nkDotExpr: op = op[1]
   var opr: PIdent
   case op.kind
   of nkSym: opr = op.sym.name

nimsuggest/tests/tcon1.nim

@@ -1,13 +1,43 @@
+## Test Invocation `con`text in various situations
+
+## various of this proc are used as the basis for these tests
 proc test(s: string; a: int) = discard
+
+## This overload should be used to ensure the lower airity `test` doesn't match
+proc test(s: string; a: string, b: int) = discard
+
+## similar signature but different name to ensure `con` doesn't get greedy
 proc testB(a, b: string) = discard
+
+# with a param already specified
 test("hello here", #[!]#)
+
+# as first param
 testB(#[!]#
 
+# dot expressions
+"from behind".test(#[!]#
+
+# two params matched, so disqualify the lower airity `test`
+# TODO: this doesn't work, because dot exprs, overloads, etc aren't currently
+#       handled by suggest.suggestCall. sigmatch.partialMatch by way of
+#       sigmatch.matchesAux. Doesn't use the operand before the dot as part of
+#       the formal parameters. Changing this is tricky because it's used by
+#       the proper compilation sem pass and that's a big change all in one go.
+"and again".test("more", #[!]#
+
 
 discard """
 $nimsuggest --tester $file
 >con $1
-con;;skProc;;tcon1.test;;proc (s: string, a: int);;$file;;1;;5;;"";;100
+con;;skProc;;tcon1.test;;proc (s: string, a: int);;$file;;4;;5;;"";;100
+con;;skProc;;tcon1.test;;proc (s: string, a: string, b: int);;$file;;7;;5;;"";;100
 >con $2
-con;;skProc;;tcon1.testB;;proc (a: string, b: string);;$file;;2;;5;;"";;100
+con;;skProc;;tcon1.testB;;proc (a: string, b: string);;$file;;10;;5;;"";;100
+>con $3
+con;;skProc;;tcon1.test;;proc (s: string, a: string, b: int);;$file;;7;;5;;"";;100
+con;;skProc;;tcon1.test;;proc (s: string, a: int);;$file;;4;;5;;"";;100
+>con $4
+con;;skProc;;tcon1.test;;proc (s: string, a: int);;$file;;4;;5;;"";;100
+con;;skProc;;tcon1.test;;proc (s: string, a: string, b: int);;$file;;7;;5;;"";;100
 """