Changing a method signature Kind: Binary-level Break Languages affected: C# (VB and F# most likely, but untested) API before change public static class Foo { public static void bar(int i); } API after change public static class Foo { public static bool bar(int i); } Sample client code working before change Foo.bar(13);
Clearly the machine code the JIT compiler can generate for the first case is much more efficient. One rule that really helps there is that an object can only be unboxed to a variable that has the same type as the boxed value. That allows the JIT compiler to generate very efficient code, no value … Read more
The answer below the line was written in 2008. C# 7 introduced pattern matching, which has largely replaced the as operator, as you can now write: if (randomObject is TargetType tt) { // Use tt here } Note that tt is still in scope after this, but not definitely assigned. (It is definitely assigned within … Read more
Strings aren’t value types since they can be huge, and need to be stored on the heap. Value types are (in all implementations of the CLR as of yet) stored on the stack. Stack allocating strings would break all sorts of things: the stack is only 1MB for 32-bit and 4MB for 64-bit, you’d have … Read more
Change the “MSBuild project build output verbosity” to “Detailed” or above. To do this, follow these steps: Bring up the Options dialog (Tools -> Options…). In the left-hand tree, select the Projects and Solutions node, and then select Build and Run. Note: if this node doesn’t show up, make sure that the checkbox at the … Read more
One of the Roslyn engineers who specializes in understanding optimization of stack usage took a look at this and reports to me that there seems to be a problem in the interaction between the way the C# compiler generates local variable stores and the way the JIT compiler does register scheduling in the corresponding x86 … Read more