Bug 5316 - AOT Compiler not constructing dictionary type in generic class.
Summary: AOT Compiler not constructing dictionary type in generic class.
Status: RESOLVED FIXED
Alias: None
Product: iOS
Classification: Xamarin
Component: General ()
Version: 5.2
Hardware: Macintosh Mac OS
: --- normal
Target Milestone: Untriaged
Assignee: Bugzilla
URL:
Depends on:
Blocks:
 
Reported: 2012-05-24 22:16 UTC by Ergwun
Modified: 2012-05-29 08:15 UTC (History)
2 users (show)

Tags:
Is this bug a regression?: ---
Last known good build:

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Status:
RESOLVED FIXED

Description Ergwun 2012-05-24 22:16:51 UTC
When creating a generic type that has a Dictionary that uses the type's generic type parameter for its values' type, the AOT compiler doesn't construct the required Dictionary type, resulting in a runtime error on an iOS device when it tries to invoke the JIT compiler.

For example:

public class Foo<T>
{
    private Dictionary<int, T> d = new Dictionary<int, T>();
    ...
}

var foo = new Foo<string>(); // Runtime error.

Writing code elsewhere to force construction of the Dictionary type with the required type parameters will work-around this problem.
Comment 1 Ergwun 2012-05-24 22:28:32 UTC
Tested on MonoTouch 5.2.12.

Only happens when dictionary key is a value type (primitive or custom), and then happens even if IEqualityComparer is passed in constructor.

Another workaround is to make the dictionary field public, and access it in code e.g.
add this line to end of unit test in attached project.
int x = foo.dict.Count;
Comment 2 Zoltan Varga 2012-05-29 07:33:09 UTC
Fixed in master/mobile-master.
Comment 3 Ergwun 2012-05-29 08:15:02 UTC
Cool, thanks.