Merge 2017-07 CWG Motion 6

Author: zygoloid

source/expressions.tex

@@ -999,7 +999,10 @@
 by \tcode{\&}. If a \grammarterm{lambda-capture} includes a
 \grammarterm{capture-default} that is \tcode{=}, each
 \grammarterm{simple-capture} of that \grammarterm{lambda-capture} shall
-be of the form ``\tcode{\&} \grammarterm{identifier}'' or ``\tcode{* this}''.
+be of the form
+``\tcode{\&} \grammarterm{identifier}'',
+``\tcode{this}'',
+or ``\tcode{* this}''.
 \begin{note} The form \tcode{[\&,this]} is redundant but accepted
 for compatibility with ISO \CppXIV. \end{note}
 Ignoring appearances in
@@ -1011,9 +1014,10 @@
 struct S2 { void f(int i); };
 void S2::f(int i) {
   [&, i]{ };        // OK
+  [&, this, i]{ };  // OK, equivalent to \tcode{[\&, i]}
   [&, &i]{ };       // error: \tcode{i} preceded by \tcode{\&} when \tcode{\&} is the default
   [=, *this]{ };    // OK
-  [=, this]{ };     // error: \tcode{this} when \tcode{=} is the default
+  [=, this]{ };     // OK, equivalent to \tcode{[=]}
   [i, i]{ };        // error: \tcode{i} repeated
   [this, *this]{ }; // error: \tcode{this} appears twice
 }