16f6c0aecf
Inline adoc files when they are included exactly once. Also fix language tags because this inlining gives us better information on what language the code is written in.
66 lines
1.6 KiB
Plaintext
66 lines
1.6 KiB
Plaintext
== Why is this an issue?
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A field marked ``++readonly++`` can only be assigned as part of its declaration or in a constructor. While ``++readonly++`` reference types (e.g. classes) can still have their state changed subsequently, the same is not true of value types such as ``++struct++`` s. Thus, calling a method that updates object state on a ``++readonly++`` value type field simply has no effect (but runs without error!). The result is code that probably doesn't do what you thought it did.
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This rule raises an issue when a method that is not marked ``++[Pure]++`` is invoked on a ``++readonly++`` value type field.
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=== Noncompliant code example
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[source,csharp]
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----
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public struct S1
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{
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public int value;
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public void SetValue()
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{
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value = 10;
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}
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}
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class Test
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{
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static readonly S1 first;
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static S1 second;
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static void Main()
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{
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first.SetValue(); // Noncompliant
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second.SetValue();
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Console.WriteLine(first.value); // Surprise! This writes 0
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Console.WriteLine(second.value); // This writes 10
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}
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}
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----
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ifdef::env-github,rspecator-view[]
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'''
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== Implementation Specification
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(visible only on this page)
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=== Message
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Remove the "readonly" modifier from "xxx", or add the "[Pure]" attribute to "yyy".
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=== Highlighting
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``++xxx.impureMethod++``
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'''
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== Comments And Links
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(visible only on this page)
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=== on 11 Dec 2015, 09:17:14 Tamas Vajk wrote:
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\[~ann.campbell.2] I changed the title a bit.
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=== on 11 Dec 2015, 15:54:48 Ann Campbell wrote:
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\[~tamas.vajk] I made one further, minor change
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endif::env-github,rspecator-view[]
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