[mojo-stdlib][******] Migrate to __init__(out self)

This adopts the recent changes that allow the use of the `out`
argument convention.  This argument convention more correctly
models the nature of `__init__` which initializes self but never
reads from it.

This was discussed on this public thread:
#3623

MODULAR_ORIG_COMMIT_REV_ID: d05be1ccb28b254aeccd5807858546aeb1777991

docs/manual/basics.ipynb

@@ -272,7 +272,7 @@
     "    var first: Int\n",
     "    var second: Int\n",
     "\n",
-    "    fn __init__(inout self, first: Int, second: Int):\n",
+    "    fn __init__(out self, first: Int, second: Int):\n",
     "        self.first = first\n",
     "        self.second = second\n",
     "\n",

docs/manual/decorators/nonmaterializable.ipynb

@@ -48,11 +48,11 @@
     "struct HasBool:\n",
     "    var x: Bool\n",
     "\n",
-    "    fn __init__(inout self, x: Bool):\n",
+    "    fn __init__(out self, x: Bool):\n",
     "        self.x = x\n",
     "\n",
     "    @always_inline(\"nodebug\")\n",
-    "    fn __init__(inout self, nms: NmStruct):\n",
+    "    fn __init__(out self, nms: NmStruct):\n",
     "        self.x = True if (nms.x == 77) else False\n",
     "\n",
     "@value\n",

docs/manual/decorators/register-passable.ipynb

@@ -42,11 +42,11 @@
                 "    var a: Int\n",
                 "    var b: Int\n",
                 "\n",
-                "    fn __init__(inout self, one: Int, two: Int):\n",
+                "    fn __init__(out self, one: Int, two: Int):\n",
                 "        self.a = one\n",
                 "        self.b = two\n",
                 "\n",
-                "    fn __copyinit__(inout self, existing: Self):\n",
+                "    fn __copyinit__(out self, existing: Self):\n",
                 "        self.a = existing.a\n",
                 "        self.b = existing.b\n",
                 "\n",

docs/manual/decorators/staticmethod.ipynb

@@ -38,10 +38,10 @@
     "struct MyStruct:\n",
     "    var data: List[UInt8]\n",
     "\n",
-    "    fn __init__(inout self):\n",
+    "    fn __init__(out self):\n",
     "        self.data = List[UInt8]()\n",
     "\n",
-    "    fn __moveinit__(inout self, owned existing: Self):\n",
+    "    fn __moveinit__(out self, owned existing: Self):\n",
     "        self.data = existing.data ^\n",
     "\n",
     "    @staticmethod\n",

docs/manual/decorators/value.ipynb

@@ -58,15 +58,15 @@
     "    var name: String\n",
     "    var age: Int\n",
     "\n",
-    "    fn __init__(inout self, owned name: String, age: Int):\n",
+    "    fn __init__(out self, owned name: String, age: Int):\n",
     "        self.name = name^\n",
     "        self.age = age\n",
     "\n",
-    "    fn __copyinit__(inout self, existing: Self):\n",
+    "    fn __copyinit__(out self, existing: Self):\n",
     "        self.name = existing.name\n",
     "        self.age = existing.age\n",
     "\n",
-    "    fn __moveinit__(inout self, owned existing: Self):\n",
+    "    fn __moveinit__(out self, owned existing: Self):\n",
     "        self.name = existing.name^\n",
     "        self.age = existing.age"
    ]

docs/manual/functions.ipynb

@@ -794,7 +794,7 @@
    "source": [
     "@value\n",
     "struct MyString:\n",
-    "    fn __init__(inout self, string: StringLiteral):\n",
+    "    fn __init__(out self, string: StringLiteral):\n",
     "        pass\n",
     "\n",
     "fn foo(name: String):\n",

docs/manual/lifecycle/death.ipynb

@@ -186,7 +186,7 @@
         "    var name: String\n",
         "    var age: Int\n",
         "\n",
-        "    fn __init__(inout self, name: String, age: Int):\n",
+        "    fn __init__(out self, name: String, age: Int):\n",
         "        self.name = name\n",
         "        self.age = age"
       ]
@@ -216,7 +216,7 @@
         "    var data: UnsafePointer[Int]\n",
         "    var size: Int\n",
         "\n",
-        "    fn __init__(inout self, size: Int, val: Int):\n",
+        "    fn __init__(out self, size: Int, val: Int):\n",
         "        self.size = size\n",
         "        self.data = UnsafePointer[Int].alloc(self.size)\n",
         "        for i in range(self.size):\n",
@@ -272,7 +272,7 @@
         "    var name: String\n",
         "    var age: Int\n",
         "\n",
-        "    fn __init__(inout self, name: String, age: Int):\n",
+        "    fn __init__(out self, name: String, age: Int):\n",
         "        self.name = name\n",
         "        self.age = age\n",
         "\n",
@@ -398,7 +398,7 @@
         "\n",
         "```mojo\n",
         "struct TwoStrings:\n",
-        "    fn __moveinit__(inout self, owned existing: Self):\n",
+        "    fn __moveinit__(out self, owned existing: Self):\n",
         "        # Initializes a new `self` by consuming the contents of `existing`\n",
         "    fn __del__(owned self):\n",
         "        # Destroys all resources in `self`\n",
@@ -448,11 +448,11 @@
         "    var str1: String\n",
         "    var str2: String\n",
         "\n",
-        "    fn __init__(inout self, one: String):\n",
+        "    fn __init__(out self, one: String):\n",
         "        self.str1 = one\n",
         "        self.str2 = String(\"bar\")\n",
         "\n",
-        "    fn __moveinit__(inout self, owned existing: Self):\n",
+        "    fn __moveinit__(out self, owned existing: Self):\n",
         "        self.str1 = existing.str1\n",
         "        self.str2 = existing.str2\n",
         "\n",

docs/manual/lifecycle/life.ipynb

@@ -104,7 +104,7 @@
     "    var name: String\n",
     "    var age: Int\n",
     "\n",
-    "    fn __init__(inout self, name: String, age: Int):\n",
+    "    fn __init__(out self, name: String, age: Int):\n",
     "        self.name = name\n",
     "        self.age = age"
    ]
@@ -181,11 +181,11 @@
     "    var name: String\n",
     "    var age: Int\n",
     "\n",
-    "    fn __init__(inout self):\n",
+    "    fn __init__(out self):\n",
     "        self.name = \"\"\n",
     "        self.age = 0\n",
     "\n",
-    "    fn __init__(inout self, name: String):\n",
+    "    fn __init__(out self, name: String):\n",
     "        self = MyPet()\n",
     "        self.name = name"
    ]
@@ -218,7 +218,7 @@
     "    var name: String\n",
     "    var age: Int\n",
     "\n",
-    "    fn __init__(inout self, name: String, age: Int, cond: Bool):\n",
+    "    fn __init__(out self, name: String, age: Int, cond: Bool):\n",
     "        self.name = name\n",
     "        if cond:\n",
     "            self.age = age\n",
@@ -254,7 +254,7 @@
     "\n",
     "```mojo\n",
     "struct Target:\n",
-    "  fn __init__(inout self, s: Source): ...\n",
+    "  fn __init__(out self, s: Source): ...\n",
     "```\n",
     "\n",
     "With implicit conversion, the assignment above is essentially identical to:\n",
@@ -269,7 +269,7 @@
     "\n",
     "```mojo\n",
     "struct Target:\n",
-    "  fn __init__(inout self, s: Source, reverse: Bool = False): ...\n",
+    "  fn __init__(out self, s: Source, reverse: Bool = False): ...\n",
     "```\n",
     "\n",
     "Implicit conversion also occurs if the type doesn't declare its own constructor,\n",
@@ -293,14 +293,14 @@
     "\n",
     "```mojo\n",
     "struct A: \n",
-    "  fn __init__(inout self, s: Source): ...\n",
+    "  fn __init__(out self, s: Source): ...\n",
     "\n",
     "struct B: \n",
-    "  fn __init__(inout self, s: Source): ...\n",
+    "  fn __init__(out self, s: Source): ...\n",
     "\n",
     "struct Target:\n",
-    "  fn __init__(inout self, a: A): ...\n",
-    "  fn __init__(inout self, b: B): ...\n",
+    "  fn __init__(out self, a: A): ...\n",
+    "  fn __init__(out self, b: B): ...\n",
     "\n",
     "# Fails\n",
     "var t = Target(Source())\n",
@@ -316,7 +316,7 @@
     "```mojo\n",
     "struct Target:\n",
     "  # does not support implicit conversion\n",
-    "  fn __init__(inout self, *, source: Source): ...\n",
+    "  fn __init__(out self, *, source: Source): ...\n",
     "\n",
     "# the constructor must be called with a keyword\n",
     "var t = Target(source=a)\n",
@@ -363,11 +363,11 @@
     "    var name: String\n",
     "    var age: Int\n",
     "\n",
-    "    fn __init__(inout self, name: String, age: Int):\n",
+    "    fn __init__(out self, name: String, age: Int):\n",
     "        self.name = name\n",
     "        self.age = age\n",
     "\n",
-    "    fn __copyinit__(inout self, existing: Self):\n",
+    "    fn __copyinit__(out self, existing: Self):\n",
     "        self.name = existing.name\n",
     "        self.age = existing.age"
    ]
@@ -433,14 +433,14 @@
     "    var size: Int\n",
     "    var cap: Int\n",
     "\n",
-    "    fn __init__(inout self, size: Int, val: Int):\n",
+    "    fn __init__(out self, size: Int, val: Int):\n",
     "        self.size = size\n",
     "        self.cap = size * 2\n",
     "        self.data = UnsafePointer[Int].alloc(self.cap)\n",
     "        for i in range(self.size):\n",
     "            (self.data + i).init_pointee_copy(val)\n",
     "\n",
-    "    fn __copyinit__(inout self, existing: Self):\n",
+    "    fn __copyinit__(out self, existing: Self):\n",
     "        # Deep-copy the existing value\n",
     "        self.size = existing.size\n",
     "        self.cap = existing.cap\n",
@@ -600,14 +600,14 @@
     "    var cap: Int\n",
     "\n",
     "\n",
-    "    fn __init__(inout self, size: Int, val: Int):\n",
+    "    fn __init__(out self, size: Int, val: Int):\n",
     "        self.size = size\n",
     "        self.cap = size * 2\n",
     "        self.data = UnsafePointer[Int].alloc(self.size)\n",
     "        for i in range(self.size):\n",
     "            (self.data + i).init_pointee_copy(val)\n",
     "\n",
-    "    fn __copyinit__(inout self, existing: Self):\n",
+    "    fn __copyinit__(out self, existing: Self):\n",
     "        # Deep-copy the existing value\n",
     "        self.size = existing.size\n",
     "        self.cap = existing.cap\n",
@@ -616,7 +616,7 @@
     "            (self.data + i).init_pointee_copy(existing.data[i])\n",
     "        # The lifetime of `existing` continues unchanged\n",
     "\n",
-    "    fn __moveinit__(inout self, owned existing: Self):\n",
+    "    fn __moveinit__(out self, owned existing: Self):\n",
     "        print(\"move\")\n",
     "        # Shallow copy the existing value\n",
     "        self.size = existing.size\n",
@@ -771,15 +771,15 @@
     "    var name: String\n",
     "    var age: Int\n",
     "\n",
-    "    fn __init__(inout self, owned name: String, age: Int):\n",
+    "    fn __init__(out self, owned name: String, age: Int):\n",
     "        self.name = name^\n",
     "        self.age = age\n",
     "\n",
-    "    fn __copyinit__(inout self, existing: Self):\n",
+    "    fn __copyinit__(out self, existing: Self):\n",
     "        self.name = existing.name\n",
     "        self.age = existing.age\n",
     "\n",
-    "    fn __moveinit__(inout self, owned existing: Self):\n",
+    "    fn __moveinit__(out self, owned existing: Self):\n",
     "        self.name = existing.name^\n",
     "        self.age = existing.age"
    ]
@@ -809,7 +809,7 @@
     "    var name: String\n",
     "    var age: Int\n",
     "\n",
-    "    fn __init__(inout self, owned name: String):\n",
+    "    fn __init__(out self, owned name: String):\n",
     "        self.name = name^\n",
     "        self.age = 0\n"
    ]

docs/manual/parameters/index.ipynb

@@ -233,7 +233,7 @@
     "    var data: UnsafePointer[ElementType]\n",
     "    var size: Int\n",
     "\n",
-    "    fn __init__(inout self, *elements: ElementType):\n",
+    "    fn __init__(out self, *elements: ElementType):\n",
     "        self.size = len(elements)\n",
     "        self.data = UnsafePointer[ElementType].alloc(self.size)\n",
     "        for i in range(self.size):\n",
@@ -438,7 +438,7 @@
     "    var value: … # Some low-level MLIR stuff here\n",
     "\n",
     "    # Create a new SIMD from a number of scalars\n",
-    "    fn __init__(inout self, *elems: SIMD[type, 1]):  ...\n",
+    "    fn __init__(out self, *elems: SIMD[type, 1]):  ...\n",
     "\n",
     "    # Fill a SIMD with a duplicated scalar value.\n",
     "    @staticmethod\n",
@@ -536,7 +536,7 @@
     "    var value: Int\n",
     "\n",
     "    @always_inline(\"nodebug\")\n",
-    "    fn __init__(inout self, _a: Int):\n",
+    "    fn __init__(out self, _a: Int):\n",
     "        self.value = _a\n",
     "\n",
     "fn foo[x: MyInt, a: Int]():\n",
@@ -569,7 +569,7 @@
     "parameter_overloads[1, 2, MyInt(3)]()\n",
     "\n",
     "struct MyStruct:\n",
-    "    fn __init__(inout self):\n",
+    "    fn __init__(out self):\n",
     "        pass\n",
     "\n",
     "    fn foo(inout self):\n",
@@ -730,7 +730,7 @@
     "struct One[Type: StringableCollectionElement]:\n",
     "    var value: Type\n",
     "\n",
-    "    fn __init__(inout self, value: Type):\n",
+    "    fn __init__(out self, value: Type):\n",
     "        self.value = value\n",
     "\n",
     "def use_one():\n",
@@ -768,7 +768,7 @@
     "    var val1: Type\n",
     "    var val2: Type\n",
     "\n",
-    "    fn __init__(inout self, one: One[Type], another: One[Type]):\n",
+    "    fn __init__(out self, one: One[Type], another: One[Type]):\n",
     "        self.val1 = one.value\n",
     "        self.val2 = another.value\n",
     "        print(str(self.val1), str(self.val2))\n",
@@ -886,7 +886,7 @@
    "outputs": [],
    "source": [
     "struct KwParamStruct[greeting: String = \"Hello\", name: String = \"🔥mojo🔥\"]:\n",
-    "    fn __init__(inout self):\n",
+    "    fn __init__(out self):\n",
     "        print(greeting, name)\n",
     "\n",
     "fn use_kw_params():\n",
@@ -1193,7 +1193,7 @@
     "    var data: UnsafePointer[T]\n",
     "    var size: Int\n",
     "\n",
-    "    fn __init__(inout self, size: Int, value: T):\n",
+    "    fn __init__(out self, size: Int, value: T):\n",
     "        self.size = size\n",
     "        self.data = UnsafePointer[T].alloc(self.size)\n",
     "        for i in range(self.size):\n",