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Specify that a void return type doesn't cause errors in checked mode.

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R=eernst@google.com

Review-Url: https://codereview.chromium.org/2875643002 .
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Lasse R.H. Nielsen 2017-05-11 14:17:55 +02:00
parent cdfe67f95d
commit 122345e356
1 changed files with 11 additions and 2 deletions
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13
docs/language/dartLangSpec.tex
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@ -6453,8 +6453,17 @@ It is a static type warning if the body of $f$ is marked \ASYNC{} and the type \
\LMHash{}
Let $S$ be the runtime type of $o$. In checked mode:
\begin{itemize}
\item If the body of $f$ is marked \ASYNC{} (\ref{functions}) it is a dynamic type error if $o$ is not \NULL{} (\ref{null}) and \code{Future<flatten(S)>} is not a subtype of the actual return type (\ref{actualTypeOfADeclaration}) of $f$.
\item Otherwise, it is a dynamic type error if $o$ is not \NULL{} and the runtime type of $o$ is not a subtype of the actual return type of $f$.
\item If the body of $f$ is marked \ASYNC{} (\ref{functions})
it is a dynamic type error if $o$ is not \NULL{} (\ref{null}),
the actual return type (\ref{actualTypeOfADeclaration}) of $f$ is not \VOID,
and \code{Future<flatten(S)>} is not a subtype of the actual return type of $f$.
% TODO(lrn): The "void foo() async { return e }" case is somewhat speculative.
% When we disallow "return e" in a void function, we might also want to revisit
% this rule. Currently it also covers the "void foo() async => e;" case, which
% we might want to allow.
\item Otherwise, it is a dynamic type error if $o$ is not \NULL{},
the actual return type of $f$ is not \VOID{},
and the runtime type of $o$ is not a subtype of the actual return type of $f$.
\end{itemize}
\LMHash{}