enable experimental:strictDefs (#24225)

lib/std/formatfloat.nim

@@ -140,4 +140,5 @@ proc addFloat*(result: var string; x: float | float32) {.inline.} =
 when defined(nimPreviewSlimSystem):
   func `$`*(x: float | float32): string =
     ## Outplace version of `addFloat`.
+    result = ""
     result.addFloat(x)

lib/std/jsonutils.nim

@@ -186,7 +186,7 @@ proc discKeyMatch[T](obj: T, json: JsonNode, key: static string): bool =
   if not json.hasKey key:
     return true
   let field = accessField(obj, key)
-  var jsonVal: typeof(field)
+  var jsonVal: typeof(field) = default(typeof(field))
   fromJson(jsonVal, json[key])
   if jsonVal != field:
     return false
@@ -293,6 +293,7 @@ proc fromJson*[T](a: var T, b: JsonNode, opt = Joptions()) =
 
 proc jsonTo*(b: JsonNode, T: typedesc, opt = Joptions()): T =
   ## reverse of `toJson`
+  result = default(T)
   fromJson(result, b, opt)
 
 proc toJson*[T](a: T, opt = initToJsonOptions()): JsonNode =

lib/std/packedsets.nim

@@ -462,7 +462,7 @@ proc union*[A](s1, s2: PackedSet[A]): PackedSet[A] =
       c = union(a, b)
     assert c.len == 5
     assert c == [1, 2, 3, 4, 5].toPackedSet
-
+  result = default(PackedSet[A])
   result.assign(s1)
   incl(result, s2)
 
@@ -509,7 +509,7 @@ proc symmetricDifference*[A](s1, s2: PackedSet[A]): PackedSet[A] =
       c = symmetricDifference(a, b)
     assert c.len == 4
     assert c == [1, 2, 4, 5].toPackedSet
-
+  result = default(PackedSet[A])
   result.assign(s1)
   for item in s2.items:
     if containsOrIncl(result, item):

lib/std/typedthreads.nim

@@ -63,7 +63,7 @@ proc threadFunc(obj: ptr seq[int]) {.thread.} =
 proc threadHandler() =
   var thr: array[0..4, Thread[ptr seq[int]]]
   var s = newSeq[int]()
-    
+
   for i in 0..high(thr):
     createThread(thr[i], threadFunc, s.addr)
   joinThreads(thr)
@@ -137,6 +137,7 @@ when defined(zephyr):
 {.push stack_trace:off.}
 when defined(windows):
   proc threadProcWrapper[TArg](closure: pointer): int32 {.stdcall.} =
+    result = 0'i32
     nimThreadProcWrapperBody(closure)
     # implicitly return 0
 elif defined(genode):
@@ -144,6 +145,7 @@ elif defined(genode):
     nimThreadProcWrapperBody(closure)
 else:
   proc threadProcWrapper[TArg](closure: pointer): pointer {.noconv.} =
+    result = nil
     nimThreadProcWrapperBody(closure)
 {.pop.}
 
@@ -164,7 +166,7 @@ when hostOS == "windows":
 
   proc joinThreads*[TArg](t: varargs[Thread[TArg]]) =
     ## Waits for every thread in `t` to finish.
-    var a: array[MAXIMUM_WAIT_OBJECTS, SysThread]
+    var a: array[MAXIMUM_WAIT_OBJECTS, SysThread] = default(array[MAXIMUM_WAIT_OBJECTS, SysThread])
     var k = 0
     while k < len(t):
       var count = min(len(t) - k, MAXIMUM_WAIT_OBJECTS)
@@ -220,7 +222,7 @@ when hostOS == "windows":
     when TArg isnot void: t.data = param
     t.dataFn = tp
     when hasSharedHeap: t.core.stackSize = ThreadStackSize
-    var dummyThreadId: int32
+    var dummyThreadId: int32 = 0'i32
     t.sys = createThread(nil, ThreadStackSize, threadProcWrapper[TArg],
                          addr(t), 0'i32, dummyThreadId)
     if t.sys <= 0:

lib/std/wrapnils.nim

@@ -58,7 +58,7 @@ proc finalize(n: NimNode, lhs: NimNode, level: int): NimNode =
   if level == 0:
     result = quote: `lhs` = `n`
   else:
-    result = quote: (let `lhs` = `n`)
+    result = quote: (var `lhs` = `n`)
 
 proc process(n: NimNode, lhs: NimNode, label: NimNode, level: int): NimNode =
   var n = n.copyNimTree
@@ -77,7 +77,7 @@ proc process(n: NimNode, lhs: NimNode, label: NimNode, level: int): NimNode =
       let check = it[1]
       let okSet = check[1]
       let kind1 = check[2]
-      let tmp = genSym(nskLet, "tmpCase")
+      let tmp = genSym(nskVar, "tmpCase")
       let body = process(objRef, tmp, label, level + 1)
       let tmp3 = nnkDerefExpr.newTree(tmp)
       it[0][0] = tmp3
@@ -91,7 +91,7 @@ proc process(n: NimNode, lhs: NimNode, label: NimNode, level: int): NimNode =
         `assgn`
       break
     elif it.kind in {nnkHiddenDeref, nnkDerefExpr}:
-      let tmp = genSym(nskLet, "tmp")
+      let tmp = genSym(nskVar, "tmp")
       let body = process(it[0], tmp, label, level + 1)
       it[0] = tmp
       let assgn = finalize(n, lhs, level)
@@ -116,7 +116,7 @@ macro `?.`*(a: typed): auto =
   let label = genSym(nskLabel, "label")
   let body = process(a, lhs, label, 0)
   result = quote do:
-    var `lhs`: type(`a`)
+    var `lhs`: type(`a`) = default(type(`a`))
     block `label`:
       `body`
     `lhs`
@@ -148,9 +148,9 @@ macro `??.`*(a: typed): Option =
   let label = genSym(nskLabel, "label")
   let body = process(a, lhs2, label, 0)
   result = quote do:
-    var `lhs`: Option[type(`a`)]
+    var `lhs`: Option[type(`a`)] = default(Option[type(`a`)])
     block `label`:
-      var `lhs2`: type(`a`)
+      var `lhs2`: type(`a`) = default(type(`a`))
       `body`
       `lhs` = option(`lhs2`)
     `lhs`