C#: Analysis change notes.

change-notes/1.21/analysis-csharp.md

@@ -18,13 +18,15 @@
 * The class `Attribute` has two new predicates: `getConstructorArgument()` and `getNamedArgument()`. The first predicate returns arguments to the underlying constructor call and the latter returns named arguments for initializing fields and properties.
 * The following QL classes have been added to model C# 8 features:
     - Class `IndexExpr` models from end index expressions, for example `^1`
-    - Class `IsRecursivePatternExpr` models `is` recursive patterns, for example `s is string { Length: 0 }`
+    - Class `PatternExpr` is an `Expr` that appears in a pattern. It has the new subclasses `DiscardPatternExpr`, `LabeledPatternExpr`, `RecursivePatternExpr`, `TypeAccessPatternExpr`, `TypePatternExpr`, and `VariablePatternExpr`.
+    - Class `PatternMatch` models a pattern being matched. It has the subclasses `Case` and `IsExpr`.
     - Class `PositionalPatternExpr` models position patterns, for example `(int x, int y)`
     - Class `PropertyPatternExpr` models property patterns, for example `Length: int len`
     - Class `RangeExpr` models range expressions, for example `1..^1`
-    - Class `RecursivePatternCase` models `case` statements using recursive patterns, for example `case string { Length: 0 } x:`
-    - Class `RecursivePatternExpr` models recursive patterns, for example `string { Length: 0 }`
     - Class `SwitchCaseExpr` models the arm of a switch expression, for example `(false, false) => true`
     - Class `SwitchExpr` models `switch` expressions, for example `(a, b) switch { ... }`
+    - Classes `IsConstantExpr`, `IsTypeExpr` and `IsPatternExpr` are deprecated in favour of `IsExpr`
+    - Class `Switch` models both `SwitchExpr` and `SwitchStmt`
+    - Class `Case` models both `CaseStmt` and `SwitchCaseExpr`
 
 ## Changes to autobuilder