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POExplanation of Oslo error "M0197: 'Text' cannot be used in a Type context"?
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  1. POExplanation of Oslo error "M0197: 'Text' cannot be used in a Type context"?
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    copied!<p>In Microsoft Oslo SDK CTP 2008 (using Intellipad) the following code compiles fine:</p> <pre><code>module M { type T { Text : Text; } } </code></pre> <p>while compiling the below code leads to the error "M0197: 'Text' cannot be used in a Type context"</p> <pre><code>module M { type T { Text : Text; Value : Text; // error } } </code></pre> <p>I do not see the difference between the examples, as in the first case Text is also used in a Type context.</p> <p>UPDATE:</p> <p>To add to the confusion, consider the following example, which also compiles fine:</p> <pre><code>module M { type X; type T { X : X; Y : X; } } </code></pre> <p>The M Language Specification states that:</p> <blockquote> <p>Field declarations override lexical scoping to prevent the type of a declaration binding to the declaration itself. The ascribed type of a field declaration must not be the declaration itself; however, the declaration may be used in a constraint. Consider the following example:</p> <p>type A; type B { A : A; }</p> <p>The lexically enclosing scope for the type ascription of the field declaration A is the entity declaration B. With no exception, the type ascription A would bind to the field declaration in a circular reference which is an error. The exception allows lexical lookup to skip the field declaration in this case. </p> </blockquote> <p>It seems that user defined types and built-in (intrinsic) types are not treated equal.</p> <p>UPDATE2:</p> <p>Note that <em>Value</em> in the above example is not a reserved keyword. The same error results if you rename <em>Value</em> to <em>Y</em>.</p> <p>Any ideas?</p> <p>Regards, tamberg</p>
 

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