Index: docs/language/dartLangSpec.tex |
diff --git a/docs/language/dartLangSpec.tex b/docs/language/dartLangSpec.tex |
index 590001560230e3797700307a1fd1bc7b570edbfd..cafc8f4b0ca58519e29f8a30a26969c20dc52ff6 100644 |
--- a/docs/language/dartLangSpec.tex |
+++ b/docs/language/dartLangSpec.tex |
@@ -21,6 +21,7 @@ |
% |
% 2.0 |
% - Don't allow functions as assert test values. |
+% - It is a static warning and dynamic error to assign to final local. |
% |
% 1.15 |
% - Change how language specification describes control flow. |
@@ -448,6 +449,7 @@ A {\em final variable} is a variable whose binding is fixed upon initialization; |
It is a static warning if a final instance variable that has been initialized at its point of declaration is also initialized in a constructor. |
% It is a static warning if a final instance variable that has been initialized by means of an initializing formal of a constructor is also initialized elsewhere in the same constructor. |
It is a compile-time error if a local variable $v$ is final and $v$ is not initialized at its point of declaration. |
+It is a static warning and a dynamic error to assign to a final local variable. |
\commentary{ |
@@ -5940,16 +5942,26 @@ It is a static warning if the static type of $c$ may not be assigned to \cd{bool |
\LMLabel{for-in} |
\LMHash{} |
-A for statement of the form \code{ \FOR{} ($finalConstVarOrType?$ id \IN{} $e$) $s$} is equivalent to the following code: |
+Let $D$ be derived from \code{finalConstVarOrType?} |
+and let $n0$ be an identifier that does not occur anywhere in the program. |
+A for statement of the form \code{\FOR{} ($D$ $id$ \IN{} $e$) $s$} is equivalent to the following code: |
\begin{dartCode} |
-var n0 = $e$.iterator; |
-\WHILE{} (n0.moveNext()) \{ |
- $finalConstVarOrType?$ id = n0.current; |
+\VAR{} $n0$ = $e$.iterator; |
+\WHILE{} ($n0$.moveNext()) \{ |
+ $D$ $id$ = $n0$.current; |
$s$ |
\} |
\end{dartCode} |
-where \code{n0} is an identifier that does not occur anywhere in the program, except that for purposes of static typechecking, it is checked under the assumption that $n0$ is declared to be of type $T$, where $T$ is the static type of $e.iterator$. |
+ |
+For purposes of static typechecking, |
+this code is checked under the assumption that $n0$ is declared to be of type $T$, |
+where $T$ is the static type of \code{$e$.iterator}. |
+ |
+\commentary{ |
+It follows that it is a static warning if $D$ is empty and $id$ is a final variable, |
+and a dynamic error will then occur if the body is executed. |
+} |
\subsubsection{Asynchronous For-in} |
\LMLabel{asynchronousFor-in} |
@@ -5958,11 +5970,16 @@ where \code{n0} is an identifier that does not occur anywhere in the program, ex |
A for-in statement may be asynchronous. The asynchronous form is designed to iterate over streams. An asynchronous for loop is distinguished by the keyword \AWAIT{} immediately preceding the keyword \FOR. |
\LMHash{} |
-Execution of a for-in statement, $f$, of the form \code{\AWAIT{} \FOR{} (finalConstVarOrType? $id$ \IN{} $e$) $s$} proceeds as follows: |
+Let $D$ be derived from \code{finalConstVarOrType?}. |
+Execution of a for-in statement, $f$, of the form |
+\code{\AWAIT{} \FOR{} ($D$ $id$ \IN{} $e$) $s$} |
+proceeds as follows: |
\LMHash{} |
The expression $e$ is evaluated to an object $o$. |
It is a dynamic error if $o$ is not an instance of a class that implements \code{Stream}. |
+It is a static warning if $D$ is empty and $id$ is a final variable, |
+and it is then a dynamic error if the body is executed. |
\LMHash{} |
The stream associated with the innermost enclosing asynchronous for loop, if any, is paused. |