early param count check for overloads

changelogs/changelog_2_0_0.md

@@ -219,6 +219,25 @@
   replacement of the `nnkFormalParams` node as well as having child nodes
   unlike other type class AST.
 
+- Overloaded routine calls will now eagerly check if the parameter counts are
+  compatible with each overload. This means `untyped` parameters will not be
+  type checked in some cases where they previously were, i.e.:
+
+  ```nim
+  template foo(x: int, body: untyped) = 
+    let value {.inject.} = x
+    body
+  template foo(body: untyped) = foo(123, body)
+
+  # previously did not compile, now compiles:
+  foo:
+    echo value # 123
+  ```
+
+  To fix cases where code depended on this old behavior, change the relevant
+  `untyped` parameters to `typed`. The switch `--legacy:noEagerParamCountMatch`
+  is also provided to use the old behavior for the time being.
+
 ## Standard library additions and changes
 
 [//]: # "Changes:"

compiler/ast.nim

@@ -521,6 +521,8 @@ type
     tfInheritable,    # is the object inheritable?
     tfHasOwned,       # type contains an 'owned' type and must be moved
     tfEnumHasHoles,   # enum cannot be mapped into a range
+                      # for objects becomes tfObjHasKids
+                      # for routines becomes tfHasVarargsParam
     tfShallow,        # type can be shallow copied on assignment
     tfThread,         # proc type is marked as ``thread``; alias for ``gcsafe``
     tfFromGeneric,    # type is an instantiation of a generic; this is needed
@@ -629,6 +631,7 @@ const
   tfUnion* = tfNoSideEffect
   tfGcSafe* = tfThread
   tfObjHasKids* = tfEnumHasHoles
+  tfHasVarargsParam* = tfEnumHasHoles ## routine type has varargs parameter
   tfReturnsNew* = tfInheritable
   skError* = skUnknown
 
@@ -917,6 +920,8 @@ type
                               # for modules, an unique index corresponding
                               # to the module's fileIdx
                               # for variables a slot index for the evaluator
+                              # for routines the minimum required parameters
+                              # (could be part of the type but no space there)
     offset*: int              # offset of record field
     loc*: TLoc
     annex*: PLib              # additional fields (seldom used, so we use a

compiler/options.nim

@@ -233,6 +233,10 @@ type
     laxEffects
       ## Lax effects system prior to Nim 2.0.
     verboseTypeMismatch
+    noEagerParamCountMatch
+      ## Routine calls will not eagerly fail a match on incompatible
+      ## parameter counts. This causes some `untyped` parameters to become
+      ## typed.
 
   SymbolFilesOption* = enum
     disabledSf, writeOnlySf, readOnlySf, v2Sf, stressTest

compiler/semtypes.nim

@@ -1281,6 +1281,7 @@ proc semProcTypeNode(c: PContext, n, genericParams: PNode,
   result = newProcType(c, n.info, prev)
   var check = initIntSet()
   var counter = 0
+  var requiredCount = 0 # minimum required parameters
 
   for i in 1..<n.len:
     var a = n[i]
@@ -1306,6 +1307,8 @@ proc semProcTypeNode(c: PContext, n, genericParams: PNode,
       if kind in {skProc, skFunc} and (typ.kind == tyTyped or typ.kind == tyUntyped):
         if not isMagic(getCurrOwner(c)):
           localError(c.config, a[^2].info, "'" & typ.sym.name.s & "' is only allowed in templates and macros or magic procs")
+      if typ.kind == tyVarargs:
+        result.flags.incl tfHasVarargsParam
 
 
     if hasDefault:
@@ -1358,6 +1361,9 @@ proc semProcTypeNode(c: PContext, n, genericParams: PNode,
         elif typ.kind == tyStatic:
           def = semConstExpr(c, def)
           def = fitNode(c, typ, def, def.info)
+    else: # no default value
+      if not (hasType and typ.kind in {tyVarargs, tyVoid}):
+        requiredCount += a.len - 2
 
     if not hasType and not hasDefault:
       if isType: localError(c.config, a.info, "':' expected")
@@ -1399,6 +1405,13 @@ proc semProcTypeNode(c: PContext, n, genericParams: PNode,
       onDef(a[j].info, arg)
       a[j] = newSymNode(arg)
 
+  if not isType:
+    # routine symbol for which the params are being checked
+    let s = result.owner
+    if s != nil:
+      # set the position field to the minimum number of required parameters
+      s.position = requiredCount
+
   var r: PType
   if n[0].kind != nkEmpty:
     r = semTypeNode(c, n[0], nil)

compiler/sigmatch.nim

@@ -2399,8 +2399,9 @@ proc findFirstArgBlock(m: var TCandidate, n: PNode): int =
 
 proc matchesAux(c: PContext, n, nOrig: PNode, m: var TCandidate, marker: var IntSet) =
 
-  template noMatch() =
-    c.mergeShadowScope #merge so that we don't have to resem for later overloads
+  template noMatch(paramScopeOpen = true) =
+    when paramScopeOpen:
+      c.mergeShadowScope #merge so that we don't have to resem for later overloads
     m.state = csNoMatch
     m.firstMismatch.arg = a
     m.firstMismatch.formal = formal
@@ -2438,6 +2439,32 @@ proc matchesAux(c: PContext, n, nOrig: PNode, m: var TCandidate, marker: var Int
     formal = if formalLen > 1: m.callee.n[1].sym else: nil # current routine parameter
     container: PNode = nil # constructed container
   let firstArgBlock = findFirstArgBlock(m, n)
+
+  # early check for parameter count (nimsuggest allows partial calls)
+  let givenCount = n.len - 1
+  let expectedCount = formalLen - f
+  if givenCount != expectedCount and
+      noEagerParamCountMatch notin c.config.legacyFeatures and
+      (when defined(nimsuggest): c.config.ideCmd notin {ideSug, ideCon} else: true):
+    # routine symbols precalculate minimum argument count in `position` field
+    # if there is no routine symbol, don't bother calculating
+    if m.callee.kind == tyProc and m.calleeSym != nil:
+      # if this fails just add it as an `and`:
+      assert m.calleeSym.kind in skProcKinds
+      # if this is unset, it's 0 by default, which matches everything anyway:
+      let minCount = m.calleeSym.position
+      if givenCount < minCount:
+        m.firstMismatch.kind = kMissingParam
+        a = givenCount + 1
+        formal = m.callee.n[a].sym
+        noMatch(paramScopeOpen = false)
+    # no max param count for varargs
+    if {tfVarargs, tfHasVarargsParam} * m.callee.flags == {}:
+      if givenCount > expectedCount:
+        m.firstMismatch.kind = kExtraArg
+        a = expectedCount + 1
+        noMatch(paramScopeOpen = false)
+
   while a < n.len:
     c.openShadowScope
 

compiler/vm.nim

@@ -1157,7 +1157,9 @@ proc rawExecute(c: PCtx, start: int, tos: PStackFrame): TFullReg =
         let nc = rcReg.node
         if nb.kind != nc.kind: discard
         elif (nb == nc) or (nb.kind == nkNilLit): ret = true # intentional
-        elif nb.kind in {nkSym, nkTupleConstr, nkClosure} and nb.typ != nil and nb.typ.kind == tyProc and sameConstant(nb, nc):
+        elif nb.typ != nil and nb.typ.kind == tyProc and
+            nb.kind in {nkSym, nkTupleConstr, nkClosure} and
+            sameConstant(nb, nc):
           ret = true
           # this also takes care of procvar's, represented as nkTupleConstr, e.g. (nil, nil)
         elif nb.kind == nkIntLit and nc.kind == nkIntLit and nb.intVal == nc.intVal: # TODO: nkPtrLit

compiler/vmgen.nim

@@ -461,8 +461,8 @@ proc sameConstant*(a, b: PNode): bool =
       # if a.floatVal == 0.0: result = cast[uint64](a.floatVal) == cast[uint64](b.floatVal)
       # else: result = a.floatVal == b.floatVal
     of nkStrLit..nkTripleStrLit: result = a.strVal == b.strVal
-    of nkType, nkNilLit: result = a.typ == b.typ
-    of nkEmpty: result = true
+    of nkType: result = a.typ == b.typ
+    of nkEmpty, nkNilLit: result = true
     else:
       if a.len == b.len:
         for i in 0..<a.len:

testament/important_packages.nim

@@ -33,7 +33,7 @@ var packages*: seq[NimblePackage]
 proc pkg(name: string; cmd = "nimble test"; url = "", useHead = true, allowFailure = false) =
   packages.add NimblePackage(name: name, cmd: cmd, url: url, useHead: useHead, allowFailure: allowFailure)
 
-pkg "alea"
+pkg "alea", "nim c --debuginfo --path:. --run --define:reportConceptFailures --legacy:noEagerParamCountMatch tests/test.nim" # pending https://github.com/andreaferretti/alea/pull/9
 pkg "argparse"
 pkg "arraymancer", "nim c tests/tests_cpu.nim"
 pkg "ast_pattern_matching", "nim c -r tests/test1.nim"

tests/concepts/t3330.nim

@@ -2,38 +2,33 @@ discard """
 matrix: "--mm:refc"
 errormsg: "type mismatch: got <Bar[system.int]>"
 nimout: '''
-t3330.nim(70, 4) Error: type mismatch: got <Bar[system.int]>
+t3330.nim(58, 4) Error: type mismatch: got <Bar[system.int]>
 but expected one of:
 proc test(foo: Foo[int])
   first type mismatch at position: 1
   required type for foo: Foo[int]
   but expression 'bar' is of type: Bar[system.int]
-t3330.nim(55, 8) Hint: Non-matching candidates for add(k, string, T)
+t3330.nim(43, 8) Hint: Non-matching candidates for add(k, string, T)
 proc add(x: var string; y: char)
-  first type mismatch at position: 1
-  required type for x: var string
-  but expression 'k' is of type: Alias
+  first type mismatch at position: 3
+  extra argument given
 proc add(x: var string; y: cstring)
-  first type mismatch at position: 1
-  required type for x: var string
-  but expression 'k' is of type: Alias
+  first type mismatch at position: 3
+  extra argument given
 proc add(x: var string; y: string)
-  first type mismatch at position: 1
-  required type for x: var string
-  but expression 'k' is of type: Alias
+  first type mismatch at position: 3
+  extra argument given
 proc add[T](x: var seq[T]; y: openArray[T])
-  first type mismatch at position: 1
-  required type for x: var seq[T]
-  but expression 'k' is of type: Alias
+  first type mismatch at position: 3
+  extra argument given
 proc add[T](x: var seq[T]; y: sink T)
-  first type mismatch at position: 1
-  required type for x: var seq[T]
-  but expression 'k' is of type: Alias
+  first type mismatch at position: 3
+  extra argument given
 
-t3330.nim(55, 8) template/generic instantiation of `add` from here
-t3330.nim(62, 6) Foo: 'bar.value' cannot be assigned to
-t3330.nim(55, 8) template/generic instantiation of `add` from here
-t3330.nim(63, 6) Foo: 'bar.x' cannot be assigned to
+t3330.nim(43, 8) template/generic instantiation of `add` from here
+t3330.nim(50, 6) Foo: 'bar.value' cannot be assigned to
+t3330.nim(43, 8) template/generic instantiation of `add` from here
+t3330.nim(51, 6) Foo: 'bar.x' cannot be assigned to
 
 expression: test(bar)'''
 """
@@ -42,14 +37,7 @@ expression: test(bar)'''
 
 
 
-
-
-
-
-
-
-
-## line 60
+## line 40
 type
   Foo[T] = concept k
     add(k, string, T)

tests/concepts/texplain.nim

@@ -1,5 +1,5 @@
 discard """
-  cmd: "nim c --verbosity:0 --colors:off $file"
+  cmd: "nim c --verbosity:0 --colors:off --showAllMismatches:on $file"
   nimout: '''
 texplain.nim(162, 10) Hint: Non-matching candidates for e(y)
 proc e(i: int): int
@@ -54,9 +54,8 @@ proc r(o: RegularConcept): int
 texplain.nim(173, 9) template/generic instantiation of `assert` from here
 texplain.nim(132, 5) RegularConcept: concept predicate failed
 proc r[T](a: SomeNumber; b: T; c: auto)
-  first type mismatch at position: 1
-  required type for a: SomeNumber
-  but expression 'n' is of type: NonMatchingType
+  first type mismatch at position: 2
+  missing parameter: b
 
 expression: r(n)
 texplain.nim(174, 20) Hint: Non-matching candidates for r(y)
@@ -65,9 +64,8 @@ proc r(i: string): int
   required type for i: string
   but expression 'y' is of type: MatchingType
 proc r[T](a: SomeNumber; b: T; c: auto)
-  first type mismatch at position: 1
-  required type for a: SomeNumber
-  but expression 'y' is of type: MatchingType
+  first type mismatch at position: 2
+  missing parameter: b
 
 texplain.nim(182, 2) Error: type mismatch: got <MatchingType>
 but expected one of:
@@ -118,6 +116,8 @@ expression: f(y)'''
 
 
 
+
+
 
 
 

tests/errmsgs/tsigmatch.nim

@@ -7,9 +7,8 @@ proc f(a: A)
   first type mismatch at position: 2
   extra argument given
 proc f(b: B)
-  first type mismatch at position: 1
-  required type for b: B
-  but expression 'A()' is of type: A
+  first type mismatch at position: 2
+  extra argument given
 
 expression: f(A(), "extra")
 tsigmatch.nim(125, 6) Error: type mismatch: got <(string, proc (){.gcsafe.})>
@@ -43,16 +42,15 @@ expression: takesFuncs([proc (x: int) {.gcsafe.} = echo [x]])
 tsigmatch.nim(149, 4) Error: type mismatch: got <int literal(10), a0: int literal(5), string>
 but expected one of:
 proc f(a0: uint8; b: string)
-  first type mismatch at position: 2
-  named param already provided: a0
+  first type mismatch at position: 3
+  extra argument given
 
 expression: f(10, a0 = 5, "")
 tsigmatch.nim(156, 4) Error: type mismatch: got <string, string, string, string, string, float64, string>
 but expected one of:
 proc f(a1: int)
-  first type mismatch at position: 1
-  required type for a1: int
-  but expression '"asdf"' is of type: string
+  first type mismatch at position: 2
+  extra argument given
 proc f(a1: string; a2: varargs[string]; a3: float; a4: var string)
   first type mismatch at position: 7
   required type for a4: var string
@@ -97,6 +95,8 @@ see also: tests/errmsgs/tdeclaredlocs.nim
 
 
 
+
+
 ## line 100
 when true:
   # bug #11061 Type mismatch error "first type mismatch at" points to wrong argument/position

tests/template/moverloadeduntypedparam.nim

@@ -0,0 +1,3 @@
+template fun2*(a: bool, body: untyped): untyped = discard
+template fun2*(a: int, body: untyped): untyped = discard
+template fun2*(body: untyped): untyped = discard