ambiguous identifier resolution

compiler/lookups.nim

@@ -558,7 +558,7 @@ proc errorUseQualifier*(c: PContext; info: TLineInfo; s: PSym) =
   var amb: bool
   discard errorUseQualifier(c, info, s, amb)
 
-proc errorUseQualifier(c: PContext; info: TLineInfo; candidates: seq[PSym]; prefix = "use one of") =
+proc errorUseQualifier*(c: PContext; info: TLineInfo; candidates: seq[PSym]; prefix = "use one of") =
   var err = "ambiguous identifier: '" & candidates[0].name.s & "'"
   var i = 0
   for candidate in candidates:
@@ -621,31 +621,36 @@ type
   TLookupFlag* = enum
     checkAmbiguity, checkUndeclared, checkModule, checkPureEnumFields
 
+const allExceptModule = {low(TSymKind)..high(TSymKind)} - {skModule, skPackage}
+
+proc lookUpCandidates*(c: PContext, ident: PIdent, filter: set[TSymKind]): seq[PSym] =
+  result = searchInScopesFilterBy(c, ident, filter)
+  if result.len == 0:
+    result.add allPureEnumFields(c, ident)
+
 proc qualifiedLookUp*(c: PContext, n: PNode, flags: set[TLookupFlag]): PSym =
-  const allExceptModule = {low(TSymKind)..high(TSymKind)} - {skModule, skPackage}
   case n.kind
   of nkIdent, nkAccQuoted:
     var amb = false
     var ident = considerQuotedIdent(c, n)
     if checkModule in flags:
       result = searchInScopes(c, ident, amb)
+      if result == nil:
+        let candidates = allPureEnumFields(c, ident)
+        if candidates.len > 0:
+          result = candidates[0]
+          amb = candidates.len > 1
+          if amb and checkAmbiguity in flags:
+            errorUseQualifier(c, n.info, candidates)
     else:
-      let candidates = searchInScopesFilterBy(c, ident, allExceptModule)
+      let candidates = lookUpCandidates(c, ident, allExceptModule)
       if candidates.len > 0:
         result = candidates[0]
         amb = candidates.len > 1
         if amb and checkAmbiguity in flags:
           errorUseQualifier(c, n.info, candidates)
       else:
         result = nil
-    if result == nil:
-      let candidates = allPureEnumFields(c, ident)
-      if candidates.len > 0:
-        result = candidates[0]
-        amb = candidates.len > 1
-        if amb and checkAmbiguity in flags:
-          errorUseQualifier(c, n.info, candidates)
-
     if result == nil and checkUndeclared in flags:
       result = errorUndeclaredIdentifierHint(c, n, ident)
     elif checkAmbiguity in flags and result != nil and amb:

compiler/semexprs.nim

@@ -131,11 +131,13 @@ proc semSym(c: PContext, n: PNode, sym: PSym, flags: TExprFlags): PNode
 proc isSymChoice(n: PNode): bool {.inline.} =
   result = n.kind in nkSymChoices
 
-proc semSymChoice(c: PContext, n: PNode, flags: TExprFlags = {}, expectedType: PType = nil): PNode =
-  result = n
+proc resolveSymChoice(c: PContext, n: var PNode, flags: TExprFlags = {}, expectedType: PType = nil) =
+  ## Attempts to resolve a symchoice `n`, `n` remains a symchoice if
+  ## it cannot be resolved (this is the case even when `n.len == 1`).
   if expectedType != nil:
-    result = fitNode(c, expectedType, result, n.info)
-  if isSymChoice(result) and efAllowSymChoice notin flags:
+    # resolve from type inference, see paramTypesMatch
+    n = fitNode(c, expectedType, n, n.info)
+  if isSymChoice(n) and efAllowSymChoice notin flags:
     # some contexts might want sym choices preserved for later disambiguation
     # in general though they are ambiguous
     let first = n[0].sym
@@ -145,17 +147,23 @@ proc semSymChoice(c: PContext, n: PNode, flags: TExprFlags = {}, expectedType: P
         foundSym == first:
       # choose the first resolved enum field, i.e. the latest in scope
       # to mirror behavior before overloadable enums
-      result = n[0]
-    else:
-      var err = "ambiguous identifier '" & first.name.s &
-        "' -- use one of the following:\n"
-      for child in n:
-        let candidate = child.sym
-        err.add "  " & candidate.owner.name.s & "." & candidate.name.s
-        err.add ": " & typeToString(candidate.typ) & "\n"
-      localError(c.config, n.info, err)
-      n.typ = errorType(c)
-      result = n
+      n = n[0]
+
+proc semSymChoice(c: PContext, n: PNode, flags: TExprFlags = {}, expectedType: PType = nil): PNode =
+  result = n
+  resolveSymChoice(c, result, flags, expectedType)
+  if isSymChoice(result) and result.len == 1:
+    result = result[0]
+  if isSymChoice(result) and efAllowSymChoice notin flags:
+    var err = "ambiguous identifier: '" & result[0].sym.name.s &
+      "' -- use one of the following:\n"
+    for child in n:
+      let candidate = child.sym
+      err.add "  " & candidate.owner.name.s & "." & candidate.name.s
+      err.add ": " & typeToString(candidate.typ) & "\n"
+    localError(c.config, n.info, err)
+    n.typ = errorType(c)
+    result = n
   if result.kind == nkSym:
     result = semSym(c, result, result.sym, flags)
 
@@ -3026,25 +3034,54 @@ proc semExpr(c: PContext, n: PNode, flags: TExprFlags = {}, expectedType: PType
   if nfSem in n.flags: return
   case n.kind
   of nkIdent, nkAccQuoted:
+    let ident = considerQuotedIdent(c, n)
     var s: PSym = nil
     if expectedType != nil and (
         let expected = expectedType.skipTypes(abstractRange-{tyDistinct});
         expected.kind == tyEnum):
-      let nameId = considerQuotedIdent(c, n).id
+      let nameId = ident.id
       for f in expected.n:
         if f.kind == nkSym and f.sym.name.id == nameId:
           s = f.sym
           break
     if s == nil:
-      let checks = if efNoEvaluateGeneric in flags:
-          {checkUndeclared, checkPureEnumFields}
-        elif efInCall in flags:
-          {checkUndeclared, checkModule, checkPureEnumFields}
+      var filter = {low(TSymKind)..high(TSymKind)}
+      if efNoEvaluateGeneric in flags:
+        # `a[...]` where `a` is a module or package is not possible
+        filter.excl {skModule, skPackage}
+      let candidates = lookUpCandidates(c, ident, filter)
+      if candidates.len == 0:
+        s = errorUndeclaredIdentifierHint(c, n, ident)
+      elif candidates.len == 1 or {efNoEvaluateGeneric, efInCall} * flags != {}:
+        # unambiguous, or we don't care about ambiguity
+        s = candidates[0]
+      else:
+        # ambiguous symbols have 1 last chance as a symchoice,
+        # but type symbols cannot participate in symchoices
+        var choice = newNodeIT(nkClosedSymChoice, n.info, newTypeS(tyNone, c))
+        for c in candidates:
+          if c.kind notin {skType, skModule, skPackage}:
+            choice.add newSymNode(c, n.info)
+        if choice.len == 0:
+          # we know candidates.len > 1, we just couldn't put any in a symchoice
+          errorUseQualifier(c, n.info, candidates)
         else:
-          {checkUndeclared, checkModule, checkAmbiguity, checkPureEnumFields}
-      s = qualifiedLookUp(c, n, checks)
-      if s == nil:
-        return
+          resolveSymChoice(c, choice, flags, expectedType)
+          # choice.len == 1 can be true here but as long as it's a symchoice
+          # it's still not resolved
+          if isSymChoice(choice):
+            if efAllowSymChoice in flags:
+              result = choice
+            else:
+              errorUseQualifier(c, n.info, candidates)
+          else:
+            if choice.kind == nkSym:
+              s = choice.sym
+            else:
+              # resolution could have generated nkHiddenStdConv etc
+              result = semExpr(c, choice, flags, expectedType)
+    if s == nil:
+      return
     if c.matchedConcept == nil: semCaptureSym(s, c.p.owner)
     case s.kind
     of skProc, skFunc, skMethod, skConverter, skIterator:

compiler/sigmatch.nim

@@ -2346,8 +2346,8 @@ proc paramTypesMatch*(m: var TCandidate, f, a: PType,
   if arg == nil or arg.kind notin nkSymChoices:
     result = paramTypesMatchAux(m, f, a, arg, argOrig)
   else:
-    let matchSet = {skProc, skFunc, skMethod, skConverter,skIterator, skMacro,
-                    skTemplate, skEnumField}
+    # symbol kinds that don't participate in symchoice type disambiguation:
+    let matchSet = {low(TSymKind)..high(TSymKind)} - {skModule, skPackage, skType}
 
     var best = -1
     result = arg

tests/enum/tambiguousoverloads.nim

@@ -9,7 +9,7 @@ block: # bug #21887
     EnumC = enum C
 
   doAssert typeof(EnumC(A)) is EnumC #[tt.Error
-                        ^ ambiguous identifier 'A' -- use one of the following:
+                        ^ ambiguous identifier: 'A' -- use one of the following:
   EnumA.A: EnumA
   EnumB.A: EnumB]#
 
@@ -21,6 +21,6 @@ block: # issue #22598
       red
 
   let a = red #[tt.Error
-          ^ ambiguous identifier 'red' -- use one of the following:
+          ^ ambiguous identifier: 'red' -- use one of the following:
   A.red: A
   B.red: B]#

tests/enum/tpure_enums_conflict.nim

@@ -1,4 +1,5 @@
 discard """
+  disabled: true # pure enums behave like overloadable enums now which give a different error message
   errormsg: "ambiguous identifier: 'amb'"
   line: 19
 """

tests/errmsgs/t8064.nim

@@ -5,5 +5,5 @@ values
 
 discard """
   # either this or "expression has no type":
-  errormsg: "ambiguous identifier 'values' -- use one of the following:"
+  errormsg: "ambiguous identifier: 'values' -- use one of the following:"
 """

tests/lookups/tambiguousemit.nim

@@ -7,6 +7,6 @@ proc foo(x: int) = discard
 proc foo(x: float) = discard
 
 {.emit: ["// ", foo].} #[tt.Error
-                ^ ambiguous identifier 'foo' -- use one of the following:
+                ^ ambiguous identifier: 'foo' -- use one of the following:
   tambiguousemit.foo: proc (x: int){.noSideEffect, gcsafe.}
   tambiguousemit.foo: proc (x: float){.noSideEffect, gcsafe.}]#

tests/lookups/tambprocvar.nim

@@ -2,7 +2,7 @@ discard """
   action: reject
   cmd: "nim check $file"
   nimout: '''
-tambprocvar.nim(15, 11) Error: ambiguous identifier 'foo' -- use one of the following:
+tambprocvar.nim(15, 11) Error: ambiguous identifier: 'foo' -- use one of the following:
   tambprocvar.foo: proc (x: int){.noSideEffect, gcsafe.}
   tambprocvar.foo: proc (x: float){.noSideEffect, gcsafe.}
 '''
@@ -16,4 +16,4 @@ block:
 
 block:
   let x = `+` #[tt.Error
-           ^ ambiguous identifier '+' -- use one of the following:]#
+          ^ ambiguous identifier: '+' -- use one of the following:]#

tests/lookups/tambsym3.nim

@@ -1,5 +1,5 @@
 discard """
-  errormsg: "ambiguous identifier 'mDec' -- use one of the following:"
+  errormsg: "ambiguous identifier: 'mDec' -- use one of the following:"
   file: "tambsym3.nim"
   line: 11
 """

tests/macros/t23032_2.nim

@@ -1,6 +1,6 @@
 discard """
   action: "reject"
-  errormsg: "ambiguous identifier '%*'"
+  errormsg: "ambiguous identifier: '%*'"
 """
 import std/macros
 

tests/pragmas/monoff1.nim

@@ -0,0 +1 @@
+proc on*() = discard

tests/pragmas/tonoff1.nim

@@ -0,0 +1,8 @@
+# issue #23002
+
+import monoff1
+
+proc test() =
+  {.warning[ProveInit]: on.}
+
+test()

tests/pragmas/tonoff2.nim

@@ -0,0 +1,14 @@
+discard """
+    action: compile
+"""
+
+# issue #22841
+
+import unittest
+
+proc on() =
+    discard
+
+suite "some suite":
+    test "some test":
+        discard