dotnet/roslyn

Conversion of a stackalloc expression

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#23,995 创建于 2018年1月2日

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 (7 评论) (1 反应) (0 负责人)C# (20,414 star) (4,257 fork)batch import
Area-CompilersBugConcept-Diagnostic ClarityFeature - Readonly Referenceshelp wanted

描述

Version Used: 2.6.0.62309 (d3f6b8e7)

Steps to Reproduce:

Compile following

using System;

unsafe class X
{
	public static void Main ()
	{
		int* stackSpan = (int*) stackalloc int[100];
	}
}

Expected Behavior:

C# 7.2 allows stackallow casts (don't really know why) but it now reports an odd error message when the casts are used with pre-7.2 only supported pointer types.

Actual Behavior:

error CS8346: Conversion of a stackalloc expression of type 'int' to type 'int*' is not possible

贡献者指南

技术栈
csharp
领域
backendtooling
议题类型
bug
难度面向新贡献者的预计实现难度，1 表示很小改动，5 表示专家级工作。
3
预计时间有经验贡献者完成调查、实现、测试并准备 pull request 的粗略时间范围。
1-2 days
活动状态议题当前的可参与程度：新鲜、活跃、陈旧、阻塞或等待维护者输入。
stale
清晰度议题是否清楚说明期望改动、验收标准和下一步。
mostly clear
前置要求
basic C# knowledgeunderstanding of pointers
新手友好度1-100 的估计分数，表示该议题对首次贡献者的友好程度。
40
研究方向
Investigate the error message for stackalloc expression conversion in the Roslyn C# compiler. Look at the semantic analysis code that handles stackalloc, likely in BoundStackalloc or similar. The error CS8346 is generated; check how the type conversion is validated and why it returns 'int' instead of 'int*'. The fix might involve updating the error message or adjusting the conversion logic in the compiler's type checking phase. Refer to the issue comments for any previous attempts or discussions.