Update coding-style.md (#405)

coding-style.md

@@ -1,19 +1,19 @@
 # C# Coding Style
 
-We follow a similar coding style as [dotnet/corefx](https://github.com/dotnet/corefx).
+We follow a similar coding style as [dotnet/runtime](https://github.com/dotnet/runtime).
 
 For non code files (xml, etc), our current best guidance is consistency. When editing files, keep new code and changes consistent with the style in the files. For new files, it should conform to the style for that component. If there is a completely new component, anything that is reasonably broadly accepted is fine.
 
 The general rule we follow is "_use Visual Studio defaults_".
 
-1. We use [Allman style](http://en.wikipedia.org/wiki/Indent_style#Allman_style) braces, where each brace begins on a new line. A single line statement block can go without braces but the block must be properly indented on its own line and must not be nested in other statement blocks that use braces. One exception is that a `using` statement is permitted to be nested within another `using` statement by starting on the following line at the same indentation level, even if the nested `using` contains a controlled block.
+1. We use [Allman style](http://en.wikipedia.org/wiki/Indent_style#Allman_style) braces, where each brace begins on a new line. A single line statement block can go without braces but the block must be properly indented on its own line and must not be nested in other statement blocks that use braces (See rule 17 for more details). One exception is that a `using` statement is permitted to be nested within another `using` statement by starting on the following line at the same indentation level, even if the nested `using` contains a controlled block.
 2. We use four spaces of indentation (no tabs).
 3. We use `_camelCase` for internal and private fields and use `readonly` where possible. Prefix internal and private instance fields with `_`, static fields with `s_` and thread static fields with `t_`. When used on static fields, `readonly` should come after `static` (e.g. `static readonly` not `readonly static`).  Public fields should be used sparingly and should use PascalCasing with no prefix when used.
 4. We avoid `this.` unless absolutely necessary. 
 5. We always specify the visibility, even if it's the default (e.g. `private string _foo` not `string _foo`). Visibility should be the first modifier (e.g. `public abstract` not `abstract public`).
 6. Namespace imports should be specified at the top of the file, *outside* of `namespace` declarations, and should be sorted alphabetically, with the exception of `System.*` namespaces, which are to be placed on top of all others.
 7. Avoid more than one empty line at any time. For example, do not have two blank lines between members of a type.
-8. Avoid spurious free spaces. For example avoid `if (someVar == 0)...`, where the dots mark the spurious free spaces. Consider enabling "View White Space (Ctrl+E, S)" if using Visual Studio to aid detection.
+8. Avoid spurious free spaces. For example avoid `if (someVar == 0)...`, where the dots mark the spurious free spaces. Consider enabling "View White Space (Ctrl+R, Ctrl+W)" or "Edit -> Advanced -> View White Space" if using Visual Studio to aid detection.
 9. If a file happens to differ in style from these guidelines (e.g. private members are named `m_member` rather than `_member`), the existing style in that file takes precedence.
 10. We only use `var` when it's obvious what the variable type is (e.g. `var stream = new FileStream(...)` not `var stream = OpenStandardInput()`).
 11. We use language keywords instead of BCL types (e.g. `int, string, float` instead of `Int32, String, Single`, etc) for both type references as well as method calls (e.g. `int.Parse` instead of `Int32.Parse`).
@@ -22,5 +22,9 @@ The general rule we follow is "_use Visual Studio defaults_".
 14. Fields should be specified at the top within type declarations.
 15. When including non-ASCII characters in the source code use Unicode escape sequences (\uXXXX) instead of literal characters. Literal non-ASCII characters occasionally get garbled by a tool or editor.
 16. When using labels (for goto), indent the label one less than the current indentation.
+17. When using a single-statement if, we follow these conventions:
+    - Never use single-line form (for example: `if (source == null) throw new ArgumentNullException("source");`)
+    - Using braces is always accepted, and required if any block of an `if`/`else if`/.../`else` compound statement uses braces or if a single statement body spans multiple lines.
+    - Braces may be omitted only if the body of *every* block associated with an `if`/`else if`/.../`else` compound statement is placed on a single line.
 
-An [EditorConfig](https://editorconfig.org "EditorConfig homepage") file (`.editorconfig`) has been provided at the root of the sqlclient repository, enabling C# auto-formatting.
+An [EditorConfig](https://editorconfig.org "EditorConfig homepage") file (`.editorconfig`) has been provided at the root of the sqlclient repository, enabling C# auto-formatting conforming to the above guidelines.