Lambda capture this by value.

README.md

@@ -9,6 +9,7 @@ C++17 includes the following new language features:
 - [folding expressions](#folding-expressions)
 - [new rules for auto deduction from braced-init-list](#new-rules-for-auto-deduction-from-braced-init-list)
 - [constexpr lambda](#constexpr-lambda)
+- [lambda capture this by value](#lambda-capture-this-by-value)
 - [inline variables](#inline-variables)
 - [nested namespaces](#nested-namespaces)
 - [structured bindings](#structured-bindings)
@@ -153,6 +154,26 @@ constexpr int addOne(int n) {
 static_assert(addOne(1) == 2);
 ```
 
+### Lambda capture `this` by value
+Capturing `this` in a lambda's environment was previously reference-only. An example of where this is problematic is asynchronous code using callbacks that require an object to be available, potentially past its lifetime. `*this` (C++17) will now make a copy of the current object, while `this` (C++11) continues to capture by reference.
+```c++
+struct MyObj {
+  int value{ 123 };
+  auto getValueCopy() {
+    return [*this] { return value; };
+  }
+  auto getValueRef() {
+    return [this] { return value; };
+  }
+};
+MyObj mo;
+auto valueCopy = mo.getValueCopy();
+auto valueRef = mo.getValueRef();
+mo.value = 321;
+valueCopy(); // 123
+valueRef(); // 321
+```
+
 ### Inline variables
 The inline specifier can be applied to variables as well as to functions. A variable declared inline has the same semantics as a function declared inline.
 ```c++