例如，该编译器知道翻译

For instance, does the compiler know to translate

string s = "test " + "this " + "function";

到

string s = "test this function";

，从而避免与字符串连接的性能影响？

and thus avoid the performance hit with the string concatenation?

推荐答案

是的。这是由C＃规范保证。这是在第7.18（在C＃3.0规范的）：

Yes. This is guaranteed by the C# specification. It's in section 7.18 (of the C# 3.0 spec):

每当EX pression满足   要求上述上市，   EX pression是在评估   编译时。这是即使真   EX pression是一个子-EX pression   包含较大的前pression   非恒定的构建

Whenever an expression fulfills the requirements listed above, the expression is evaluated at compile-time. This is true even if the expression is a sub-expression of a larger expression that contains non-constant constructs.

（下称上面列出的要求，包括+运算符应用到两个恒定的前pressions。）

(The "requirements listed above" including the + operator applied to two constant expressions.)

另请参阅这个问题。