Comments to TI Capture Conversion

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JanUlrich 2024-03-06 19:28:33 +01:00
parent 903b2405b1
commit b1ce0f771b

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@ -240,6 +240,21 @@ The method call \texttt{shuffle(l)} is not correct, because there is no solution
$\exptype{List}{\wctype{\rwildcard{X}}{List}{\rwildcard{X}}} \lessdotCC \exptype{List}{\exptype{List}{\wtv{x}}}$
\section{Type Inference for Capture Conversion}
why do we need a lessdotCC constraint
input is e.m(e);
Recap: TI for FGJ without Wildcards
- usually the type of e must be subtypes of the method parameters
- in case of a polymorphic method: type placeholders resemble type parameters
involving wildcards:
- depending on the type of e a capture conversion must be applied first
- the captured type N must be a subtype of the method parameters
- type parameters: can be set to free variables!
- but must afterwards be closed again
- the free variables can only be used inside the let statement
- we align the let statements in a way thate mimics Java capture conversion:
% $\exptype{List}{String} <: \wctype{\wildcard{X}{\bot}{\type{Object}}}{List}{\rwildcard{X}}$