fix tnoop

This commit requires further investigation.

Fixing semExpr(nkCall) once and for all to work with sym-choices and to
allow overloading with immediate templates and macros will probably set
this straight too.

compiler/ast.nim

@@ -354,6 +354,7 @@ type
     nfTransf,   # node has been transformed
     nfSem       # node has been checked for semantics
     nfDelegate  # the call can use a delegator
+    nfExprCall  # this is an attempt to call a regular expression
 
   TNodeFlags* = set[TNodeFlag]
   TTypeFlag* = enum   # keep below 32 for efficiency reasons (now: 23)

compiler/semcall.nim

@@ -128,9 +128,14 @@ proc resolveOverloads(c: PContext, n, orig: PNode,
       pickBest(callOp)
 
     if result.state == csEmpty:
-      errors = @[]
-      pickBest(f)
-      NotFoundError(c, n, errors)
+      if nfExprCall in n.flags:
+        if c.inCompilesContext > 0 or gErrorCounter == 0:
+          LocalError(n.info, errExprXCannotBeCalled,
+                     renderTree(n, {renderNoComments}))
+      else:
+        errors = @[]
+        pickBest(f)
+        NotFoundError(c, n, errors)
       return
 
   if alt.state == csMatch and cmpCandidates(result, alt) == 0 and

compiler/semexprs.nim

@@ -732,14 +732,12 @@ proc semIndirectOp(c: PContext, n: PNode, flags: TExprFlags): PNode =
     # Now that nkSym does not imply an iteration over the proc/iterator space,
     # the old ``prc`` (which is likely an nkIdent) has to be restored:
     if result == nil: 
+      # XXX: hmm, what kind of symbols will end up here?
+      # do we really need to try the overload resolution?
       n.sons[0] = prc
       nOrig.sons[0] = prc
+      n.flags.incl nfExprCall
       result = semOverloadedCallAnalyseEffects(c, n, nOrig, flags)
-    if result == nil:
-      if c.inCompilesContext > 0 or gErrorCounter == 0:
-        LocalError(n.info, errExprXCannotBeCalled,
-                   renderTree(n, {renderNoComments}))
-      return errorNode(c, n)
   #result = afterCallActions(c, result, nOrig, flags)
   fixAbstractType(c, result)
   analyseIfAddressTakenInCall(c, result)

tests/reject/tnoop.nim

@@ -3,11 +3,10 @@ discard """
   line: 11
   errormsg: "expression \'a()\' cannot be called"
 """
-# Tests the new check in the semantic pass
-
-var
-  a: int
-
-a()  #ERROR_MSG expression 'a()' cannot be called
+# Tests the new check in the semantic pass
 
+var
+  a: int
+
+a()  #ERROR_MSG expression 'a()' cannot be called