codeql/change-notes/1.22/analysis-csharp.md

Improvements to C# analysis

Changes to existing queries

Query	Expected impact	Change
Added lines (cs/vcs/added-lines-per-file)	No results	Query has been removed.
Churned lines (cs/vcs/churn-per-file)	No results	Query has been removed.
Constant condition (cs/constant-condition)	Fewer false positive results	Results have been removed for default cases (_) in switch expressions.
Defect filter	No results	Query has been removed.
Defect from SVN	No results	Query has been removed.
Deleted lines (cs/vcs/deleted-lines-per-file)	No results	Query has been removed.
Dispose may not be called if an exception is thrown during execution (cs/dispose-not-called-on-throw)	Fewer false positive results	Results have been removed where an object is disposed both by a using statement and a Dispose call.
Files edited in pairs	No results	Query has been removed.
Filter: only files recently edited	No results	Query has been removed.
Large files currently edited	No results	Query has been removed.
Metric from SVN	No results	Query has been removed.
Number of authors (version control) (cs/vcs/authors-per-file)	No results	Query has been removed.
Number of file-level changes (cs/vcs/commits-per-file)	No results	Query has been removed.
Number of co-committed files (cs/vcs/co-commits-per-file)	No results	Query has been removed.
Number of file re-commits (cs/vcs/recommits-per-file)	No results	Query has been removed.
Number of recent file changes (cs/vcs/recent-commits-per-file)	No results	Query has been removed.
Number of authors	No results	Query has been removed.
Number of commits	No results	Query has been removed.
Poorly documented files with many authors	No results	Query has been removed.
Recent activity	No results	Query has been removed.
Unchecked return value (cs/unchecked-return-value)	Fewer false positive results	Method calls that are expression bodies of void callables (for example, the call to Foo in void Bar() => Foo()) are no longer considered to use the return value.

Changes to code extraction

• The following C# 8 features are now extracted:
  • Suppress-nullable-warning expressions, for example x!
  • Nullable reference types, for example string?

Changes to QL libraries

• The new class AnnotatedType models types with type annotations, including nullability information, return kinds (ref and readonly ref), and parameter kinds (in, out, and ref)
  • The new predicate Assignable.getAnnotatedType() gets the annotated type of an assignable (such as a variable or a property)
  • The new predicates Callable.getAnnotatedReturnType() and DelegateType.getAnnotatedReturnType() get the annotated type of the return value
  • The new predicate ArrayType.getAnnotatedElementType() gets the annotated type of the array element
  • The new predicate ConstructedGeneric.getAnnotatedTypeArgument() gets the annotated type of a type argument
  • The new predicate TypeParameterConstraints.getAnAnnotatedTypeConstraint() gets a type constraint with type annotations
• The new class SuppressNullableWarningExpr models suppress-nullable-warning expressions such as x!
• The data-flow library (and taint-tracking library) now supports flow through fields. All existing configurations will have field-flow enabled by default, but it can be disabled by adding override int fieldFlowBranchLimit() { result = 0 } to the configuration class. Field assignments, this.Foo = x, object initializers, new C() { Foo = x }, and field initializers int Foo = 0 are supported.

Changes to autobuilder