Merge branch 'devel' into ringabout-patch-5

.github/workflows/bisects.yml

@@ -8,7 +8,7 @@ jobs:
  test:
  runs-on: ubuntu-latest
  steps:
- - uses: actions/checkout@v3
+ - uses: actions/checkout@v4
 
  # nimrun-action requires Nim installed.
  - uses: jiro4989/setup-nim-action@v1

.github/workflows/ci_bench.yml

@@ -17,7 +17,7 @@ jobs:
  timeout-minutes: 60 # refs bug #18178
  steps:
  - name: 'Checkout'
- uses: actions/checkout@v3
+ uses: actions/checkout@v4
  with:
  fetch-depth: 2
 
@@ -60,7 +60,7 @@ jobs:
  run: nim c -r -d:release ci/action.nim
 
  - name: 'Checkout minimize'
- uses: actions/checkout@v3
+ uses: actions/checkout@v4
  with:
  repository: 'nim-lang/ci_bench'
  path: minimize

.github/workflows/ci_docs.yml

@@ -55,7 +55,7 @@ jobs:
 
  steps:
  - name: 'Checkout'
- uses: actions/checkout@v3
+ uses: actions/checkout@v4
  with:
  fetch-depth: 2
 

.github/workflows/ci_packages.yml

@@ -28,7 +28,7 @@ jobs:
  NIM_TESTAMENT_BATCH: ${{ matrix.batch }}
  steps:
  - name: 'Checkout'
- uses: actions/checkout@v3
+ uses: actions/checkout@v4
  with:
  fetch-depth: 2
 

.github/workflows/ci_publish.yml

@@ -17,7 +17,7 @@ jobs:
  runs-on: ${{ matrix.os }}
  steps:
  - name: 'Checkout'
- uses: actions/checkout@v3
+ uses: actions/checkout@v4
  with:
  fetch-depth: 2
 

changelog.md

@@ -11,7 +11,8 @@
 
 [//]: # "Additions:"
 
-- Adds `newStringUninit` to system, which creates a new string of length `len` like `newString` but with uninitialized content.
+- Added `newStringUninit` to system, which creates a new string of length `len` like `newString` but with uninitialized content.
+- Added `hasDefaultValue` to `std/typetraits` to check if a type has a valid default value.
 
 [//]: # "Deprecations:"
 

compiler/lookups.nim

@@ -596,7 +596,7 @@ proc lookUp*(c: PContext, n: PNode): PSym =
  if result == nil: result = errorUndeclaredIdentifierHint(c, n, ident)
  else:
  internalError(c.config, n.info, "lookUp")
- return
+ return nil
  if amb:
  #contains(c.ambiguousSymbols, result.id):
  result = errorUseQualifier(c, n.info, result, amb)

compiler/semmagic.nim

@@ -197,6 +197,8 @@ proc evalTypeTrait(c: PContext; traitCall: PNode, operand: PType, context: PSym)
  let complexObj = containsGarbageCollectedRef(t) or
  hasDestructor(t)
  result = newIntNodeT(toInt128(ord(not complexObj)), traitCall, c.idgen, c.graph)
+ of "hasDefaultValue":
+ result = newIntNodeT(toInt128(ord(not operand.requiresInit)), traitCall, c.idgen, c.graph)
  of "isNamedTuple":
  var operand = operand.skipTypes({tyGenericInst})
  let cond = operand.kind == tyTuple and operand.n != nil

compiler/sempass2.nim

@@ -352,20 +352,25 @@ proc useVar(a: PEffects, n: PNode) =
  a.init.add s.id
  useVarNoInitCheck(a, n, s)
 
+type
+ BreakState = enum
+ bsNone
+ bsBreakOrReturn
+ bsNoReturn
 
 type
  TIntersection = seq[tuple[id, count: int]] # a simple count table
 
-proc addToIntersection(inter: var TIntersection, s: int, initOnly: bool) =
+proc addToIntersection(inter: var TIntersection, s: int, state: BreakState) =
  for j in 0..<inter.len:
  if s == inter[j].id:
- if not initOnly:
+ if state == bsNone:
  inc inter[j].count
  return
- if initOnly:
- inter.add((id: s, count: 0))
- else:
+ if state == bsNone:
  inter.add((id: s, count: 1))
+ else:
+ inter.add((id: s, count: 0))
 
 proc throws(tracked, n, orig: PNode) =
  if n.typ == nil or n.typ.kind != tyError:
@@ -469,7 +474,7 @@ proc trackTryStmt(tracked: PEffects, n: PNode) =
  track(tracked, n[0])
  dec tracked.inTryStmt
  for i in oldState..<tracked.init.len:
- addToIntersection(inter, tracked.init[i], false)
+ addToIntersection(inter, tracked.init[i], bsNone)
 
  var branches = 1
  var hasFinally = false
@@ -504,7 +509,7 @@ proc trackTryStmt(tracked: PEffects, n: PNode) =
  tracked.init.add b[j][2].sym.id
  track(tracked, b[^1])
  for i in oldState..<tracked.init.len:
- addToIntersection(inter, tracked.init[i], false)
+ addToIntersection(inter, tracked.init[i], bsNone)
  else:
  setLen(tracked.init, oldState)
  track(tracked, b[^1])
@@ -673,15 +678,50 @@ proc trackOperandForIndirectCall(tracked: PEffects, n: PNode, formals: PType; ar
  localError(tracked.config, n.info, $n & " is not GC safe")
  notNilCheck(tracked, n, paramType)
 
-proc breaksBlock(n: PNode): bool =
+
+proc breaksBlock(n: PNode): BreakState =
  # semantic check doesn't allow statements after raise, break, return or
  # call to noreturn proc, so it is safe to check just the last statements
  var it = n
  while it.kind in {nkStmtList, nkStmtListExpr} and it.len > 0:
  it = it.lastSon
 
- result = it.kind in {nkBreakStmt, nkReturnStmt, nkRaiseStmt} or
- it.kind in nkCallKinds and it[0].kind == nkSym and sfNoReturn in it[0].sym.flags
+ case it.kind
+ of nkBreakStmt, nkReturnStmt:
+ result = bsBreakOrReturn
+ of nkRaiseStmt:
+ result = bsNoReturn
+ of nkCallKinds:
+ if it[0].kind == nkSym and sfNoReturn in it[0].sym.flags:
+ result = bsNoReturn
+ else:
+ result = bsNone
+ else:
+ result = bsNone
+
+proc addIdToIntersection(tracked: PEffects, inter: var TIntersection, resCounter: var int,
+ hasBreaksBlock: BreakState, oldState: int, resSym: PSym, hasResult: bool) =
+ if hasResult:
+ var alreadySatisfy = false
+
+ if hasBreaksBlock == bsNoReturn:
+ alreadySatisfy = true
+ inc resCounter
+
+ for i in oldState..<tracked.init.len:
+ if tracked.init[i] == resSym.id:
+ if not alreadySatisfy:
+ inc resCounter
+ alreadySatisfy = true
+ else:
+ addToIntersection(inter, tracked.init[i], hasBreaksBlock)
+ else:
+ for i in oldState..<tracked.init.len:
+ addToIntersection(inter, tracked.init[i], hasBreaksBlock)
+
+template hasResultSym(s: PSym): bool =
+ s != nil and s.kind in {skProc, skFunc, skConverter, skMethod} and
+ not isEmptyType(s.typ[0])
 
 proc trackCase(tracked: PEffects, n: PNode) =
  track(tracked, n[0])
@@ -694,6 +734,10 @@ proc trackCase(tracked: PEffects, n: PNode) =
  (tracked.config.hasWarn(warnProveField) or strictCaseObjects in tracked.c.features)
  var inter: TIntersection = @[]
  var toCover = 0
+ let hasResult = hasResultSym(tracked.owner)
+ let resSym = if hasResult: tracked.owner.ast[resultPos].sym else: nil
+ var resCounter = 0
+
  for i in 1..<n.len:
  let branch = n[i]
  setLen(tracked.init, oldState)
@@ -703,13 +747,14 @@ proc trackCase(tracked: PEffects, n: PNode) =
  for i in 0..<branch.len:
  track(tracked, branch[i])
  let hasBreaksBlock = breaksBlock(branch.lastSon)
- if not hasBreaksBlock:
+ if hasBreaksBlock == bsNone:
  inc toCover
- for i in oldState..<tracked.init.len:
- addToIntersection(inter, tracked.init[i], hasBreaksBlock)
+ addIdToIntersection(tracked, inter, resCounter, hasBreaksBlock, oldState, resSym, hasResult)
 
  setLen(tracked.init, oldState)
  if not stringCase or lastSon(n).kind == nkElse:
+ if hasResult and resCounter == n.len-1:
+ tracked.init.add resSym.id
  for id, count in items(inter):
  if count >= toCover: tracked.init.add id
  # else we can't merge
@@ -723,14 +768,17 @@ proc trackIf(tracked: PEffects, n: PNode) =
  addFact(tracked.guards, n[0][0])
  let oldState = tracked.init.len
 
+ let hasResult = hasResultSym(tracked.owner)
+ let resSym = if hasResult: tracked.owner.ast[resultPos].sym else: nil
+ var resCounter = 0
+
  var inter: TIntersection = @[]
  var toCover = 0
  track(tracked, n[0][1])
  let hasBreaksBlock = breaksBlock(n[0][1])
- if not hasBreaksBlock:
+ if hasBreaksBlock == bsNone:
  inc toCover
- for i in oldState..<tracked.init.len:
- addToIntersection(inter, tracked.init[i], hasBreaksBlock)
+ addIdToIntersection(tracked, inter, resCounter, hasBreaksBlock, oldState, resSym, hasResult)
 
  for i in 1..<n.len:
  let branch = n[i]
@@ -743,13 +791,14 @@ proc trackIf(tracked: PEffects, n: PNode) =
  for i in 0..<branch.len:
  track(tracked, branch[i])
  let hasBreaksBlock = breaksBlock(branch.lastSon)
- if not hasBreaksBlock:
+ if hasBreaksBlock == bsNone:
  inc toCover
- for i in oldState..<tracked.init.len:
- addToIntersection(inter, tracked.init[i], hasBreaksBlock)
+ addIdToIntersection(tracked, inter, resCounter, hasBreaksBlock, oldState, resSym, hasResult)
 
  setLen(tracked.init, oldState)
  if lastSon(n).len == 1:
+ if hasResult and resCounter == n.len:
+ tracked.init.add resSym.id
  for id, count in items(inter):
  if count >= toCover: tracked.init.add id
  # else we can't merge as it is not exhaustive

lib/pure/typetraits.nim

@@ -96,6 +96,23 @@ proc supportsCopyMem*(t: typedesc): bool {.magic: "TypeTrait".}
  ##
  ## Other languages name a type like these `blob`:idx:.
 
+proc hasDefaultValue*(t: typedesc): bool {.magic: "TypeTrait".} =
+ ## Returns true if `t` has a valid default value.
+ runnableExamples:
+ {.experimental: "strictNotNil".}
+ type
+ NilableObject = ref object
+ a: int
+ Object = NilableObject not nil
+ RequiresInit[T] = object
+ a {.requiresInit.}: T
+
+ assert hasDefaultValue(NilableObject)
+ assert not hasDefaultValue(Object)
+ assert hasDefaultValue(string)
+ assert not hasDefaultValue(var string)
+ assert not hasDefaultValue(RequiresInit[int])
+
 proc isNamedTuple*(T: typedesc): bool {.magic: "TypeTrait".} =
  ## Returns true for named tuples, false for any other type.
  runnableExamples:

tests/init/tcompiles.nim

@@ -0,0 +1,64 @@
+discard """
+ matrix: "--warningAsError:ProveInit --warningAsError:Uninit"
+"""
+
+{.experimental: "strictdefs".}
+
+type Test = object
+ id: int
+
+proc foo {.noreturn.} = discard
+
+block:
+ proc test(x: bool): Test =
+ if x:
+ foo()
+ else:
+ foo()
+
+block:
+ proc test(x: bool): Test =
+ if x:
+ result = Test()
+ else:
+ foo()
+
+ discard test(true)
+
+block:
+ proc test(x: bool): Test =
+ if x:
+ result = Test()
+ else:
+ return Test()
+
+ discard test(true)
+
+block:
+ proc test(x: bool): Test =
+ if x:
+ return Test()
+ else:
+ return Test()
+
+ discard test(true)
+
+block:
+ proc test(x: bool): Test =
+ if x:
+ result = Test()
+ else:
+ result = Test()
+ return
+
+ discard test(true)
+
+block:
+ proc test(x: bool): Test =
+ if x:
+ result = Test()
+ return
+ else:
+ raise newException(ValueError, "unreachable")
+
+ discard test(true)