Does C# optimize the concatenation of string literals?
.net, c#, optimization, performance
Solution
Yes. This is guaranteed by the C# specification. It's in section 7.18 (of the C# 3.0 spec):
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.
(The "requirements listed above" include the + operator applied to two constant expressions.)
See also this question.
Problem
For instance, does the compiler know to translate ``` string s = "test " + "this " + "function"; ``` to ``` string s = "test this function"; ``` and thus avoid the performance hit with the string concatenation?