diff --git a/csharp/extractor/Semmle.Extraction.CSharp/Entities/Expressions/IsPattern.cs b/csharp/extractor/Semmle.Extraction.CSharp/Entities/Expressions/IsPattern.cs
index 647f3efd8b1a..eb895d774bbd 100644
--- a/csharp/extractor/Semmle.Extraction.CSharp/Entities/Expressions/IsPattern.cs
+++ b/csharp/extractor/Semmle.Extraction.CSharp/Entities/Expressions/IsPattern.cs
@@ -18,13 +18,20 @@ public static Expression CreatePattern(this Context cx, PatternSyntax syntax, IE
                 case DeclarationPatternSyntax declPattern:
                     // Creates a single local variable declaration.
                     {
-                        if (declPattern.Designation is VariableDesignationSyntax designation && cx.Model(syntax).GetDeclaredSymbol(designation) is ILocalSymbol symbol)
+                        if (declPattern.Designation is VariableDesignationSyntax designation)
                         {
-                            var type = Type.Create(cx, symbol.Type);
-
-                            return VariableDeclaration.Create(cx, symbol, type, cx.Create(syntax.GetLocation()), cx.Create(designation.GetLocation()), false, parent, child);
+                            if (cx.Model(syntax).GetDeclaredSymbol(designation) is ILocalSymbol symbol)
+                            {
+                                var type = Type.Create(cx, symbol.Type);
+                                return VariableDeclaration.Create(cx, symbol, type, declPattern.Type, cx.Create(syntax.GetLocation()), cx.Create(designation.GetLocation()), false, parent, child);
+                            }
+                            if (designation is DiscardDesignationSyntax)
+                            {
+                                return Expressions.TypeAccess.Create(cx, declPattern.Type, parent, child);
+                            }
+                            throw new InternalError(designation, "Designation pattern not handled");
                         }
-                        throw new InternalError(syntax, "Is pattern not handled");
+                        throw new InternalError(declPattern, "Declaration pattern not handled");
                     }
 
                 case RecursivePatternSyntax recPattern:
@@ -40,7 +47,7 @@ public static Expression CreatePattern(this Context cx, PatternSyntax syntax, IE
                             {
                                 var type = Type.Create(cx, symbol.Type);
 
-                                return VariableDeclaration.Create(cx, symbol, type, cx.Create(syntax.GetLocation()), cx.Create(varDesignation.GetLocation()), false, parent, child);
+                                return VariableDeclaration.Create(cx, symbol, type, null, cx.Create(syntax.GetLocation()), cx.Create(varDesignation.GetLocation()), false, parent, child);
                             }
                             else
                             {
@@ -54,7 +61,7 @@ public static Expression CreatePattern(this Context cx, PatternSyntax syntax, IE
                     return new Discard(cx, dp, parent, child);
 
                 default:
-                    throw new InternalError(syntax, "Is pattern not handled");
+                    throw new InternalError(syntax, "Pattern not handled");
             }
         }
     }
@@ -108,7 +115,7 @@ public RecursivePattern(Context cx, RecursivePatternSyntax syntax, IExpressionPa
             {
                 var type = Type.Create(cx, symbol.Type);
 
-                VariableDeclaration.Create(cx, symbol, type, cx.Create(syntax.GetLocation()), cx.Create(designation.GetLocation()), false, this, 0);
+                VariableDeclaration.Create(cx, symbol, type, null, cx.Create(syntax.GetLocation()), cx.Create(designation.GetLocation()), false, this, 0);
             }
 
             if (syntax.PositionalPatternClause is PositionalPatternClauseSyntax posPc)
@@ -131,19 +138,14 @@ private IsPattern(ExpressionNodeInfo info) : base(info.SetKind(ExprKind.IS))
 
         private void PopulatePattern(PatternSyntax pattern, TypeSyntax optionalType, SyntaxToken varKeyword, VariableDesignationSyntax designation)
         {
-            bool isVar = optionalType is null;
-            if (!isVar)
-                Expressions.TypeAccess.Create(cx, optionalType, this, 1);
-
+            var isVar = optionalType is null;
             if (!(designation is null) && cx.Model(pattern).GetDeclaredSymbol(designation) is ILocalSymbol symbol)
             {
                 var type = Type.Create(cx, symbol.Type);
-
-                if (isVar)
-                    new Expression(new ExpressionInfo(cx, type, cx.Create(varKeyword.GetLocation()), ExprKind.TYPE_ACCESS, this, 1, false, null));
-
-                VariableDeclaration.Create(cx, symbol, type, cx.Create(pattern.GetLocation()), cx.Create(designation.GetLocation()), isVar, this, 2);
+                VariableDeclaration.Create(cx, symbol, type, optionalType, cx.Create(pattern.GetLocation()), cx.Create(designation.GetLocation()), isVar, this, 1);
             }
+            else if (!isVar)
+                Expressions.TypeAccess.Create(cx, optionalType, this, 1);
         }
 
         protected override void Populate()
@@ -152,7 +154,7 @@ protected override void Populate()
             switch (Syntax.Pattern)
             {
                 case ConstantPatternSyntax constantPattern:
-                    Create(cx, constantPattern.Expression, this, 3);
+                    Create(cx, constantPattern.Expression, this, 1);
                     return;
                 case VarPatternSyntax varPattern:
                     PopulatePattern(varPattern, null, varPattern.VarKeyword, varPattern.Designation);
@@ -161,7 +163,7 @@ protected override void Populate()
                     PopulatePattern(declPattern, declPattern.Type, default(SyntaxToken), declPattern.Designation);
                     return;
                 case RecursivePatternSyntax recPattern:
-                    new RecursivePattern(cx, recPattern, this, 3);
+                    new RecursivePattern(cx, recPattern, this, 1);
                     return;
                 default:
                     throw new InternalError(Syntax, "Is pattern not handled");
diff --git a/csharp/extractor/Semmle.Extraction.CSharp/Entities/Expressions/Query.cs b/csharp/extractor/Semmle.Extraction.CSharp/Entities/Expressions/Query.cs
index d8eec9b3a013..95b592bbf2a9 100644
--- a/csharp/extractor/Semmle.Extraction.CSharp/Entities/Expressions/Query.cs
+++ b/csharp/extractor/Semmle.Extraction.CSharp/Entities/Expressions/Query.cs
@@ -66,12 +66,13 @@ protected Expression DeclareRangeVariable(Context cx, IExpressionParentEntity pa
                 Extraction.Entities.Location nameLoc;
 
                 Type declType;
+                TypeSyntax declTypeSyntax = null;
                 if (getElement)
                 {
                     var from = node as FromClauseSyntax;
-                    declType = from != null && from.Type != null
-                         ? Type.Create(cx, cx.GetType(from.Type))
-                         : type.ElementType;
+                    (declType, declTypeSyntax) = from != null && from.Type != null
+                         ? (Type.Create(cx, cx.GetType(from.Type)), from.Type)
+                         : (type.ElementType, null);
                 }
                 else
                     declType = type;
@@ -79,6 +80,7 @@ protected Expression DeclareRangeVariable(Context cx, IExpressionParentEntity pa
                 var decl = VariableDeclaration.Create(cx,
                     variableSymbol,
                     declType,
+                    declTypeSyntax,
                     cx.Create(node.GetLocation()),
                     nameLoc = cx.Create(name.GetLocation()),
                     true,
diff --git a/csharp/extractor/Semmle.Extraction.CSharp/Entities/Expressions/Switch.cs b/csharp/extractor/Semmle.Extraction.CSharp/Entities/Expressions/Switch.cs
index a39bc78c8538..0d83f0db7729 100644
--- a/csharp/extractor/Semmle.Extraction.CSharp/Entities/Expressions/Switch.cs
+++ b/csharp/extractor/Semmle.Extraction.CSharp/Entities/Expressions/Switch.cs
@@ -18,7 +18,7 @@ protected override void Populate()
         {
             SwitchedExpr = Expression.Create(cx, Syntax.GoverningExpression, this, -1);
             int child = 0;
-            foreach(var arm in Syntax.Arms)
+            foreach (var arm in Syntax.Arms)
             {
                 new SwitchCase(cx, arm, this, child++);
             }
diff --git a/csharp/extractor/Semmle.Extraction.CSharp/Entities/Expressions/VariableDeclaration.cs b/csharp/extractor/Semmle.Extraction.CSharp/Entities/Expressions/VariableDeclaration.cs
index 3a8949f8fd77..0ed01e12bd9a 100644
--- a/csharp/extractor/Semmle.Extraction.CSharp/Entities/Expressions/VariableDeclaration.cs
+++ b/csharp/extractor/Semmle.Extraction.CSharp/Entities/Expressions/VariableDeclaration.cs
@@ -11,10 +11,15 @@ class VariableDeclaration : Expression
     {
         VariableDeclaration(IExpressionInfo info) : base(info) { }
 
-        public static VariableDeclaration Create(Context cx, ISymbol symbol, Type type, Extraction.Entities.Location exprLocation, Extraction.Entities.Location declLocation, bool isVar, IExpressionParentEntity parent, int child)
+        public static VariableDeclaration Create(Context cx, ISymbol symbol, Type type, TypeSyntax optionalSyntax, Extraction.Entities.Location exprLocation, Extraction.Entities.Location declLocation, bool isVar, IExpressionParentEntity parent, int child)
         {
             var ret = new VariableDeclaration(new ExpressionInfo(cx, type, exprLocation, ExprKind.LOCAL_VAR_DECL, parent, child, false, null));
-            cx.Try(null, null, () => LocalVariable.Create(cx, symbol, ret, isVar, declLocation));
+            cx.Try(null, null, () =>
+            {
+                LocalVariable.Create(cx, symbol, ret, isVar, declLocation);
+                if (optionalSyntax != null)
+                    TypeMention.Create(cx, optionalSyntax, parent, type);
+            });
             return ret;
         }
 
@@ -65,7 +70,7 @@ public static Expression CreateParenthesized(Context cx, VarPatternSyntax varPat
             {
                 var child0 = 0;
                 foreach (var variable in designation.Variables)
-                    switch(variable)
+                    switch (variable)
                     {
                         case ParenthesizedVariableDesignationSyntax paren:
                             CreateParenthesized(cx, varPattern, paren, tuple, child0++);
@@ -97,7 +102,7 @@ public static Expression CreateParenthesized(Context cx, VarPatternSyntax varPat
 
         static Expression Create(Context cx, DeclarationExpressionSyntax node, VariableDesignationSyntax designation, IExpressionParentEntity parent, int child)
         {
-            switch(designation)
+            switch (designation)
             {
                 case SingleVariableDesignationSyntax single:
                     return CreateSingle(cx, node, single, parent, child);
diff --git a/csharp/extractor/Semmle.Extraction.CSharp/Entities/Statements/Case.cs b/csharp/extractor/Semmle.Extraction.CSharp/Entities/Statements/Case.cs
index db64d79ad8e4..f4a78353b5c2 100644
--- a/csharp/extractor/Semmle.Extraction.CSharp/Entities/Statements/Case.cs
+++ b/csharp/extractor/Semmle.Extraction.CSharp/Entities/Statements/Case.cs
@@ -67,27 +67,23 @@ class CasePattern : Case<CasePatternSwitchLabelSyntax>
         private CasePattern(Context cx, CasePatternSwitchLabelSyntax node, Switch parent, int child)
             : base(cx, node, parent, child) { }
 
-        private void PopulatePattern(PatternSyntax pattern, TypeSyntax optionalType, SyntaxToken varKeyword, VariableDesignationSyntax designation)
+        private void PopulatePattern(PatternSyntax pattern, TypeSyntax optionalType, VariableDesignationSyntax designation)
         {
             var isVar = optionalType is null;
-            if (!isVar)
-                Expressions.TypeAccess.Create(cx, optionalType, this, 1);
-
             switch (designation)
             {
                 case SingleVariableDesignationSyntax _:
                     if (cx.Model(pattern).GetDeclaredSymbol(designation) is ILocalSymbol symbol)
                     {
                         var type = Type.Create(cx, symbol.Type);
-
-                        if (isVar)
-                            new Expression(new ExpressionInfo(cx, type, cx.Create(varKeyword.GetLocation()), ExprKind.TYPE_ACCESS, this, 1, false, null));
-
-                        Expressions.VariableDeclaration.Create(cx, symbol, type, cx.Create(pattern.GetLocation()), cx.Create(designation.GetLocation()), isVar, this, 0);
+                        Expressions.VariableDeclaration.Create(cx, symbol, type, optionalType, cx.Create(pattern.GetLocation()), cx.Create(designation.GetLocation()), isVar, this, 0);
                     }
                     break;
                 case DiscardDesignationSyntax discard:
-                    new Expressions.Discard(cx, discard, this, 0);
+                    if (isVar)
+                        new Expressions.Discard(cx, discard, this, 0);
+                    else
+                        Expressions.TypeAccess.Create(cx, optionalType, this, 0);
                     break;
                 case null:
                     break;
@@ -104,10 +100,10 @@ protected override void Populate()
             switch (Stmt.Pattern)
             {
                 case VarPatternSyntax varPattern:
-                    PopulatePattern(varPattern, null, varPattern.VarKeyword, varPattern.Designation);
+                    PopulatePattern(varPattern, null, varPattern.Designation);
                     break;
                 case DeclarationPatternSyntax declarationPattern:
-                    PopulatePattern(declarationPattern, declarationPattern.Type, default(SyntaxToken), declarationPattern.Designation);
+                    PopulatePattern(declarationPattern, declarationPattern.Type, declarationPattern.Designation);
                     break;
                 case ConstantPatternSyntax pattern:
                     Expression.Create(cx, pattern.Expression, this, 0);
@@ -121,7 +117,7 @@ protected override void Populate()
 
             if (Stmt.WhenClause != null)
             {
-                Expression.Create(cx, Stmt.WhenClause.Condition, this, 2);
+                Expression.Create(cx, Stmt.WhenClause.Condition, this, 1);
             }
         }
 
diff --git a/csharp/extractor/Semmle.Extraction.CSharp/Entities/Statements/ForEach.cs b/csharp/extractor/Semmle.Extraction.CSharp/Entities/Statements/ForEach.cs
index 2c3076757c26..e31f6336c138 100644
--- a/csharp/extractor/Semmle.Extraction.CSharp/Entities/Statements/ForEach.cs
+++ b/csharp/extractor/Semmle.Extraction.CSharp/Entities/Statements/ForEach.cs
@@ -27,8 +27,9 @@ protected override void Populate()
             var location = cx.Create(Stmt.Identifier.GetLocation());
 
             if (typeSymbol.Name != "_")
-                Expressions.VariableDeclaration.Create(cx, typeSymbol, type, location, location, Stmt.Type.IsVar, this, 0);
-            TypeMention.Create(cx, Stmt.Type, this, type);
+                Expressions.VariableDeclaration.Create(cx, typeSymbol, type, Stmt.Type, location, location, Stmt.Type.IsVar, this, 0);
+            else
+                TypeMention.Create(cx, Stmt.Type, this, type);
 
             Statement.Create(cx, Stmt.Statement, this, 2);
         }
diff --git a/csharp/ql/src/Bad Practices/Control-Flow/ConstantCondition.ql b/csharp/ql/src/Bad Practices/Control-Flow/ConstantCondition.ql
index e347f1c8a27f..07a0233a156c 100644
--- a/csharp/ql/src/Bad Practices/Control-Flow/ConstantCondition.ql	
+++ b/csharp/ql/src/Bad Practices/Control-Flow/ConstantCondition.ql	
@@ -72,7 +72,8 @@ class ConstantNullnessCondition extends ConstantCondition {
   ConstantNullnessCondition() {
     forex(ControlFlow::Node cfn | cfn = this.getAControlFlowNode() |
       exists(ControlFlow::SuccessorTypes::NullnessSuccessor t, ControlFlow::Node s |
-        s = cfn.getASuccessorByType(t) |
+        s = cfn.getASuccessorByType(t)
+      |
         b = t.getValue() and
         not s.isJoin()
       ) and
diff --git a/csharp/ql/src/semmle/code/csharp/Assignable.qll b/csharp/ql/src/semmle/code/csharp/Assignable.qll
index aace6270c2fb..489dc14e9b6e 100644
--- a/csharp/ql/src/semmle/code/csharp/Assignable.qll
+++ b/csharp/ql/src/semmle/code/csharp/Assignable.qll
@@ -306,9 +306,8 @@ module AssignableInternal {
   /** A local variable declaration at the top-level of a pattern. */
   class TopLevelPatternDecl extends LocalVariableDeclExpr {
     private PatternMatch pm;
-    TopLevelPatternDecl() {
-      this = pm.getPattern().(BindingPatternExpr).getVariableDeclExpr()
-    }
+
+    TopLevelPatternDecl() { this = pm.getPattern().(BindingPatternExpr).getVariableDeclExpr() }
 
     PatternMatch getMatch() { result = pm }
   }
diff --git a/csharp/ql/src/semmle/code/csharp/ExprOrStmtParent.qll b/csharp/ql/src/semmle/code/csharp/ExprOrStmtParent.qll
index 68547763f44c..d207557adbf0 100644
--- a/csharp/ql/src/semmle/code/csharp/ExprOrStmtParent.qll
+++ b/csharp/ql/src/semmle/code/csharp/ExprOrStmtParent.qll
@@ -19,17 +19,8 @@ predicate expr_parent_top_level_adjusted(Expr child, int i, @top_level_exprorstm
 }
 
 /**
- * Holds if `case` statement `cs` is a type check of the form `case int _`,
- * where `ta` is the type access `int`.
- */
-private predicate discardTypeCaseStmt(CaseStmt cs, TypeAccess ta) {
-  expr_parent(ta, 1, cs) and
-  expr_parent(any(DiscardExpr de), 0, cs)
-}
-
-/**
- * The `expr_parent()` relation adjusted for expandable assignments, `is` expressions,
- * and `case` statements. For example, the assignment `x += y` is extracted as
+ * The `expr_parent()` relation adjusted for expandable assignments. For example,
+ * the assignment `x += y` is extracted as
  *
  * ```
  *          +=
@@ -78,35 +69,7 @@ private predicate expr_parent_adjusted(Expr child, int i, ControlFlowElement par
         not ao.hasExpandedAssignment() and
         expr_parent(child, i, parent)
       )
-  else
-    if parent instanceof IsExpr
-    then
-      i = 0 and
-      expr_parent(child, i, parent)
-      or
-      // e.g. `x is string s` or `x is null`
-      i = 1 and
-      expr_parent(child, any(int j | j in [2 .. 3]), parent)
-      or
-      // e.g. `x is string`
-      i = 1 and
-      not expr_parent(_, any(int j | j in [2 .. 3]), parent) and
-      expr_parent(child, i, parent)
-    else
-      if parent instanceof CaseStmt
-      then
-        // e.g. `case string s:` or `case 5:`
-        i = 0 and
-        expr_parent(child, i, parent) and
-        not discardTypeCaseStmt(parent, _)
-        or
-        // e.g. `case string _`
-        i = 0 and
-        discardTypeCaseStmt(parent, child)
-        or
-        i = 1 and
-        expr_parent(child, 2, parent)
-      else expr_parent(child, i, parent)
+  else expr_parent(child, i, parent)
 }
 
 /**
diff --git a/csharp/ql/src/semmle/code/csharp/controlflow/internal/Completion.qll b/csharp/ql/src/semmle/code/csharp/controlflow/internal/Completion.qll
index ee85d9cb2805..a71195b776c7 100644
--- a/csharp/ql/src/semmle/code/csharp/controlflow/internal/Completion.qll
+++ b/csharp/ql/src/semmle/code/csharp/controlflow/internal/Completion.qll
@@ -417,9 +417,7 @@ predicate switchMatching(Switch s, Case c, PatternExpr pe) {
   pe = c.getPattern()
 }
 
-private predicate mustHaveMatchingCompletion(Switch s, PatternExpr pe) {
-  switchMatching(s, _, pe)
-}
+private predicate mustHaveMatchingCompletion(Switch s, PatternExpr pe) { switchMatching(s, _, pe) }
 
 /**
  * Holds if a normal completion of `cfe` must be a matching completion. Thats is,
diff --git a/csharp/ql/src/semmle/code/csharp/exprs/Expr.qll b/csharp/ql/src/semmle/code/csharp/exprs/Expr.qll
index 06ea66a5f7a4..be3c0290132b 100644
--- a/csharp/ql/src/semmle/code/csharp/exprs/Expr.qll
+++ b/csharp/ql/src/semmle/code/csharp/exprs/Expr.qll
@@ -313,6 +313,7 @@ class ConstantPatternExpr extends PatternExpr {
  */
 class TypePatternExpr extends PatternExpr {
   private Type t;
+
   TypePatternExpr() {
     t = this.(TypeAccess).getTarget() or
     t = this.(LocalVariableDeclExpr).getVariable().getType()
@@ -517,7 +518,7 @@ class Case extends PatternMatch, @case {
   /**
    * Gets the `when` expression of this case, if any. For example, `s.Length < 10`
    * in `string s when s.Length < 10 => s`
-    */
+   */
   Expr getCondition() { none() }
 
   /** Gets the body of this `case`. */
diff --git a/csharp/ql/test/library-tests/controlflow/graph/EntryElement.expected b/csharp/ql/test/library-tests/controlflow/graph/EntryElement.expected
index d71e2ffde2fb..d1543f3920a3 100644
--- a/csharp/ql/test/library-tests/controlflow/graph/EntryElement.expected
+++ b/csharp/ql/test/library-tests/controlflow/graph/EntryElement.expected
@@ -1241,11 +1241,9 @@
 | Switch.cs:46:17:46:17 | access to parameter o | Switch.cs:46:17:46:17 | access to parameter o |
 | Switch.cs:48:13:48:23 | case ...: | Switch.cs:48:13:48:23 | case ...: |
 | Switch.cs:48:18:48:20 | access to type Int32 | Switch.cs:48:18:48:20 | access to type Int32 |
-| Switch.cs:48:22:48:22 | _ | Switch.cs:48:22:48:22 | _ |
 | Switch.cs:49:17:49:22 | break; | Switch.cs:49:17:49:22 | break; |
 | Switch.cs:50:13:50:39 | case ...: | Switch.cs:50:13:50:39 | case ...: |
 | Switch.cs:50:18:50:21 | access to type Boolean | Switch.cs:50:18:50:21 | access to type Boolean |
-| Switch.cs:50:23:50:23 | _ | Switch.cs:50:23:50:23 | _ |
 | Switch.cs:50:30:50:30 | access to parameter o | Switch.cs:50:30:50:30 | access to parameter o |
 | Switch.cs:50:30:50:38 | ... != ... | Switch.cs:50:30:50:30 | access to parameter o |
 | Switch.cs:50:35:50:38 | null | Switch.cs:50:35:50:38 | null |
@@ -1267,7 +1265,6 @@
 | Switch.cs:68:25:68:25 | access to parameter s | Switch.cs:68:25:68:25 | access to parameter s |
 | Switch.cs:70:13:70:24 | case ...: | Switch.cs:70:13:70:24 | case ...: |
 | Switch.cs:70:18:70:20 | access to type Int32 | Switch.cs:70:18:70:20 | access to type Int32 |
-| Switch.cs:70:22:70:22 | _ | Switch.cs:70:22:70:22 | _ |
 | Switch.cs:71:15:71:20 | break; | Switch.cs:71:15:71:20 | break; |
 | Switch.cs:72:13:72:21 | case ...: | Switch.cs:72:13:72:21 | case ...: |
 | Switch.cs:72:18:72:19 | "" | Switch.cs:72:18:72:19 | "" |
@@ -1295,7 +1292,6 @@
 | Switch.cs:93:17:93:17 | access to parameter o | Switch.cs:93:17:93:17 | access to parameter o |
 | Switch.cs:95:13:95:24 | case ...: | Switch.cs:95:13:95:24 | case ...: |
 | Switch.cs:95:18:95:20 | access to type Int32 | Switch.cs:95:18:95:20 | access to type Int32 |
-| Switch.cs:95:22:95:22 | _ | Switch.cs:95:22:95:22 | _ |
 | Switch.cs:96:15:96:26 | return ...; | Switch.cs:96:22:96:25 | true |
 | Switch.cs:96:22:96:25 | true | Switch.cs:96:22:96:25 | true |
 | Switch.cs:98:9:98:21 | return ...; | Switch.cs:98:16:98:20 | false |
diff --git a/csharp/ql/test/library-tests/controlflow/graph/ExitElement.expected b/csharp/ql/test/library-tests/controlflow/graph/ExitElement.expected
index 82b3fa26268d..dac67a0c2220 100644
--- a/csharp/ql/test/library-tests/controlflow/graph/ExitElement.expected
+++ b/csharp/ql/test/library-tests/controlflow/graph/ExitElement.expected
@@ -1588,14 +1588,12 @@
 | Switch.cs:48:13:48:23 | case ...: | Switch.cs:49:17:49:22 | break; | break |
 | Switch.cs:48:18:48:20 | access to type Int32 | Switch.cs:48:18:48:20 | access to type Int32 | match |
 | Switch.cs:48:18:48:20 | access to type Int32 | Switch.cs:48:18:48:20 | access to type Int32 | no-match |
-| Switch.cs:48:22:48:22 | _ | Switch.cs:48:22:48:22 | _ | normal |
 | Switch.cs:49:17:49:22 | break; | Switch.cs:49:17:49:22 | break; | break |
 | Switch.cs:50:13:50:39 | case ...: | Switch.cs:50:18:50:21 | access to type Boolean | no-match |
 | Switch.cs:50:13:50:39 | case ...: | Switch.cs:50:30:50:38 | ... != ... | false/false |
 | Switch.cs:50:13:50:39 | case ...: | Switch.cs:51:17:51:22 | break; | break |
 | Switch.cs:50:18:50:21 | access to type Boolean | Switch.cs:50:18:50:21 | access to type Boolean | match |
 | Switch.cs:50:18:50:21 | access to type Boolean | Switch.cs:50:18:50:21 | access to type Boolean | no-match |
-| Switch.cs:50:23:50:23 | _ | Switch.cs:50:23:50:23 | _ | normal |
 | Switch.cs:50:30:50:30 | access to parameter o | Switch.cs:50:30:50:30 | access to parameter o | normal |
 | Switch.cs:50:30:50:38 | ... != ... | Switch.cs:50:30:50:38 | ... != ... | false/false |
 | Switch.cs:50:30:50:38 | ... != ... | Switch.cs:50:30:50:38 | ... != ... | true/true |
@@ -1626,7 +1624,6 @@
 | Switch.cs:70:13:70:24 | case ...: | Switch.cs:70:18:70:20 | access to type Int32 | no-match |
 | Switch.cs:70:13:70:24 | case ...: | Switch.cs:71:15:71:20 | break; | break |
 | Switch.cs:70:18:70:20 | access to type Int32 | Switch.cs:70:18:70:20 | access to type Int32 | no-match |
-| Switch.cs:70:22:70:22 | _ | Switch.cs:70:22:70:22 | _ | normal |
 | Switch.cs:71:15:71:20 | break; | Switch.cs:71:15:71:20 | break; | break |
 | Switch.cs:72:13:72:21 | case ...: | Switch.cs:72:18:72:19 | "" | no-match |
 | Switch.cs:72:13:72:21 | case ...: | Switch.cs:73:15:73:20 | break; | break |
@@ -1672,7 +1669,6 @@
 | Switch.cs:95:13:95:24 | case ...: | Switch.cs:96:15:96:26 | return ...; | return |
 | Switch.cs:95:18:95:20 | access to type Int32 | Switch.cs:95:18:95:20 | access to type Int32 | match |
 | Switch.cs:95:18:95:20 | access to type Int32 | Switch.cs:95:18:95:20 | access to type Int32 | no-match |
-| Switch.cs:95:22:95:22 | _ | Switch.cs:95:22:95:22 | _ | normal |
 | Switch.cs:96:15:96:26 | return ...; | Switch.cs:96:15:96:26 | return ...; | return |
 | Switch.cs:96:22:96:25 | true | Switch.cs:96:22:96:25 | true | normal |
 | Switch.cs:98:9:98:21 | return ...; | Switch.cs:98:9:98:21 | return ...; | return |
diff --git a/csharp/ql/test/library-tests/controlflow/guards/GuardedControlFlowNode.expected b/csharp/ql/test/library-tests/controlflow/guards/GuardedControlFlowNode.expected
index 28191f68ec9f..00053c4fe8e5 100644
--- a/csharp/ql/test/library-tests/controlflow/guards/GuardedControlFlowNode.expected
+++ b/csharp/ql/test/library-tests/controlflow/guards/GuardedControlFlowNode.expected
@@ -168,20 +168,20 @@
 | Guards.cs:269:11:269:12 | access to parameter o1 | Guards.cs:268:13:268:41 | call to operator == | Guards.cs:268:13:268:14 | access to parameter o1 | true |
 | Guards.cs:269:11:269:12 | access to parameter o1 | Guards.cs:268:16:268:25 | call to method GetType | Guards.cs:268:13:268:14 | access to parameter o1 | non-null |
 | Guards.cs:271:11:271:12 | access to parameter o1 | Guards.cs:270:13:270:42 | call to operator == | Guards.cs:270:13:270:14 | access to parameter o1 | true |
-| Guards.cs:279:17:279:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | match Action<Object> a |
+| Guards.cs:279:17:279:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | match access to type Action<Object> |
 | Guards.cs:279:17:279:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | non-null |
 | Guards.cs:283:17:283:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | match "" |
-| Guards.cs:283:17:283:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | non-match Action<Object> a |
 | Guards.cs:283:17:283:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | non-match Action<String> a |
+| Guards.cs:283:17:283:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | non-match access to type Action<Object> |
 | Guards.cs:283:17:283:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | non-null |
 | Guards.cs:285:17:285:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | match null |
 | Guards.cs:285:17:285:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | non-match "" |
-| Guards.cs:285:17:285:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | non-match Action<Object> a |
 | Guards.cs:285:17:285:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | non-match Action<String> a |
+| Guards.cs:285:17:285:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | non-match access to type Action<Object> |
 | Guards.cs:285:17:285:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | null |
 | Guards.cs:287:17:287:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | non-match "" |
-| Guards.cs:287:17:287:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | non-match Action<Object> a |
 | Guards.cs:287:17:287:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | non-match Action<String> a |
+| Guards.cs:287:17:287:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | non-match access to type Action<Object> |
 | Guards.cs:287:17:287:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | non-match null |
 | Guards.cs:287:17:287:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | non-null |
 | Splitting.cs:13:17:13:17 | [b (line 9): true] access to parameter o | Splitting.cs:12:17:12:17 | access to parameter o | Splitting.cs:12:17:12:17 | access to parameter o | non-null |
diff --git a/csharp/ql/test/library-tests/controlflow/guards/GuardedExpr.expected b/csharp/ql/test/library-tests/controlflow/guards/GuardedExpr.expected
index 5a59ee7ea595..711cf7785213 100644
--- a/csharp/ql/test/library-tests/controlflow/guards/GuardedExpr.expected
+++ b/csharp/ql/test/library-tests/controlflow/guards/GuardedExpr.expected
@@ -168,20 +168,20 @@
 | Guards.cs:269:11:269:12 | access to parameter o1 | Guards.cs:268:13:268:41 | call to operator == | Guards.cs:268:13:268:14 | access to parameter o1 | true |
 | Guards.cs:269:11:269:12 | access to parameter o1 | Guards.cs:268:16:268:25 | call to method GetType | Guards.cs:268:13:268:14 | access to parameter o1 | non-null |
 | Guards.cs:271:11:271:12 | access to parameter o1 | Guards.cs:270:13:270:42 | call to operator == | Guards.cs:270:13:270:14 | access to parameter o1 | true |
-| Guards.cs:279:17:279:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | match Action<Object> a |
+| Guards.cs:279:17:279:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | match access to type Action<Object> |
 | Guards.cs:279:17:279:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | non-null |
 | Guards.cs:283:17:283:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | match "" |
-| Guards.cs:283:17:283:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | non-match Action<Object> a |
 | Guards.cs:283:17:283:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | non-match Action<String> a |
+| Guards.cs:283:17:283:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | non-match access to type Action<Object> |
 | Guards.cs:283:17:283:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | non-null |
 | Guards.cs:285:17:285:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | match null |
 | Guards.cs:285:17:285:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | non-match "" |
-| Guards.cs:285:17:285:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | non-match Action<Object> a |
 | Guards.cs:285:17:285:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | non-match Action<String> a |
+| Guards.cs:285:17:285:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | non-match access to type Action<Object> |
 | Guards.cs:285:17:285:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | null |
 | Guards.cs:287:17:287:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | non-match "" |
-| Guards.cs:287:17:287:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | non-match Action<Object> a |
 | Guards.cs:287:17:287:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | non-match Action<String> a |
+| Guards.cs:287:17:287:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | non-match access to type Action<Object> |
 | Guards.cs:287:17:287:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | non-match null |
 | Guards.cs:287:17:287:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | non-null |
 | Splitting.cs:13:17:13:17 | access to parameter o | Splitting.cs:12:17:12:17 | access to parameter o | Splitting.cs:12:17:12:17 | access to parameter o | non-null |
diff --git a/csharp/ql/test/library-tests/controlflow/guards/Guards.cs b/csharp/ql/test/library-tests/controlflow/guards/Guards.cs
index 404e179b3a90..c81cc67c27c4 100644
--- a/csharp/ql/test/library-tests/controlflow/guards/Guards.cs
+++ b/csharp/ql/test/library-tests/controlflow/guards/Guards.cs
@@ -275,7 +275,7 @@ string M23(object o)
     {
         return o switch
         {
-            Action<object> a =>
+            Action<object> _ =>
                 o.ToString(), // null guarded
             Action<string> a =>
                 a.ToString(), // not null (but not a guard)
diff --git a/csharp/ql/test/library-tests/controlflow/guards/Implications.expected b/csharp/ql/test/library-tests/controlflow/guards/Implications.expected
index 05cdb7319eec..c2274d5508db 100644
--- a/csharp/ql/test/library-tests/controlflow/guards/Implications.expected
+++ b/csharp/ql/test/library-tests/controlflow/guards/Implications.expected
@@ -350,8 +350,8 @@
 | Guards.cs:270:16:270:25 | call to method GetType | non-null | Guards.cs:270:13:270:14 | access to parameter o1 | non-null |
 | Guards.cs:270:33:270:42 | call to method GetType | non-null | Guards.cs:270:30:270:31 | access to parameter o2 | non-null |
 | Guards.cs:276:16:276:16 | access to parameter o | match "" | Guards.cs:276:16:276:16 | access to parameter o | non-null |
-| Guards.cs:276:16:276:16 | access to parameter o | match Action<Object> a | Guards.cs:276:16:276:16 | access to parameter o | non-null |
 | Guards.cs:276:16:276:16 | access to parameter o | match Action<String> a | Guards.cs:276:16:276:16 | access to parameter o | non-null |
+| Guards.cs:276:16:276:16 | access to parameter o | match access to type Action<Object> | Guards.cs:276:16:276:16 | access to parameter o | non-null |
 | Guards.cs:276:16:276:16 | access to parameter o | match null | Guards.cs:276:16:276:16 | access to parameter o | null |
 | Guards.cs:276:16:276:16 | access to parameter o | non-match null | Guards.cs:276:16:276:16 | access to parameter o | non-null |
 | Guards.cs:281:17:281:17 | access to local variable a | non-null | Guards.cs:276:16:276:16 | access to parameter o | non-null |
diff --git a/csharp/ql/test/library-tests/controlflow/guards/MatchingGuardedExpr.expected b/csharp/ql/test/library-tests/controlflow/guards/MatchingGuardedExpr.expected
index 8d901cb09eaf..d74c6339eb79 100644
--- a/csharp/ql/test/library-tests/controlflow/guards/MatchingGuardedExpr.expected
+++ b/csharp/ql/test/library-tests/controlflow/guards/MatchingGuardedExpr.expected
@@ -10,15 +10,15 @@
 | Guards.cs:162:24:162:24 | access to parameter o | Guards.cs:151:17:151:17 | access to parameter o | Guards.cs:155:13:155:34 | case ...: | non-match Action<String> a | false |
 | Guards.cs:162:24:162:24 | access to parameter o | Guards.cs:151:17:151:17 | access to parameter o | Guards.cs:157:13:157:20 | case ...: | non-match "" | false |
 | Guards.cs:162:24:162:24 | access to parameter o | Guards.cs:151:17:151:17 | access to parameter o | Guards.cs:159:13:159:22 | case ...: | non-match null | false |
-| Guards.cs:279:17:279:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:278:13:279:28 | ... => ... | match Action<Object> a | true |
-| Guards.cs:283:17:283:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:278:13:279:28 | ... => ... | non-match Action<Object> a | false |
+| Guards.cs:279:17:279:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:278:13:279:28 | ... => ... | match access to type Action<Object> | true |
+| Guards.cs:283:17:283:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:278:13:279:28 | ... => ... | non-match access to type Action<Object> | false |
 | Guards.cs:283:17:283:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:280:13:281:28 | ... => ... | non-match Action<String> a | false |
 | Guards.cs:283:17:283:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:282:13:283:28 | ... => ... | match "" | true |
-| Guards.cs:285:17:285:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:278:13:279:28 | ... => ... | non-match Action<Object> a | false |
+| Guards.cs:285:17:285:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:278:13:279:28 | ... => ... | non-match access to type Action<Object> | false |
 | Guards.cs:285:17:285:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:280:13:281:28 | ... => ... | non-match Action<String> a | false |
 | Guards.cs:285:17:285:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:282:13:283:28 | ... => ... | non-match "" | false |
 | Guards.cs:285:17:285:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:284:13:285:28 | ... => ... | match null | true |
-| Guards.cs:287:17:287:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:278:13:279:28 | ... => ... | non-match Action<Object> a | false |
+| Guards.cs:287:17:287:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:278:13:279:28 | ... => ... | non-match access to type Action<Object> | false |
 | Guards.cs:287:17:287:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:280:13:281:28 | ... => ... | non-match Action<String> a | false |
 | Guards.cs:287:17:287:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:282:13:283:28 | ... => ... | non-match "" | false |
 | Guards.cs:287:17:287:17 | access to parameter o | Guards.cs:276:16:276:16 | access to parameter o | Guards.cs:284:13:285:28 | ... => ... | non-match null | false |
diff --git a/csharp/ql/test/library-tests/csharp7/Discards.expected b/csharp/ql/test/library-tests/csharp7/Discards.expected
index 6bc6b40aa71e..41f6e47ac17e 100644
--- a/csharp/ql/test/library-tests/csharp7/Discards.expected
+++ b/csharp/ql/test/library-tests/csharp7/Discards.expected
@@ -6,4 +6,3 @@
 | CSharp7.cs:224:17:224:17 | _ | Double |
 | CSharp7.cs:224:28:224:28 | _ | Boolean |
 | CSharp7.cs:225:10:225:10 | _ | Int32 |
-| CSharp7.cs:267:25:267:25 | _ | null |
diff --git a/csharp/ql/test/library-tests/csharp7/TypeCase2.ql b/csharp/ql/test/library-tests/csharp7/TypeCase2.ql
index 7d86470709a1..3d2d5e7981d3 100644
--- a/csharp/ql/test/library-tests/csharp7/TypeCase2.ql
+++ b/csharp/ql/test/library-tests/csharp7/TypeCase2.ql
@@ -1,6 +1,7 @@
 import csharp
 
 from Case c, boolean isVar, VariablePatternExpr vpe
-where vpe = c.getPattern() and
- if vpe.isImplicitlyTyped() then isVar = true else isVar = false
+where
+  vpe = c.getPattern() and
+  if vpe.isImplicitlyTyped() then isVar = true else isVar = false
 select c, vpe, vpe.getType().toString(), isVar
diff --git a/csharp/ql/test/library-tests/csharp8/patterns.cs b/csharp/ql/test/library-tests/csharp8/patterns.cs
index 36aeb1a18912..f2de7a1dad77 100644
--- a/csharp/ql/test/library-tests/csharp8/patterns.cs
+++ b/csharp/ql/test/library-tests/csharp8/patterns.cs
@@ -137,7 +137,9 @@ void Expressions2(object o)
             {
                 1 => throw new ArgumentException(),
                 2 => 3,
-                object y when y is {} => 4
+                object y when y is {} => 4,
+                string _ => 5,
+                MyStruct { X: 10 } _ => 6
             };
         }
         catch(InvalidOperationException ex)
diff --git a/csharp/ql/test/library-tests/csharp8/patterns.expected b/csharp/ql/test/library-tests/csharp8/patterns.expected
index 09ea3fd68c93..87ae263997e3 100644
--- a/csharp/ql/test/library-tests/csharp8/patterns.expected
+++ b/csharp/ql/test/library-tests/csharp8/patterns.expected
@@ -3,7 +3,7 @@ switchExprs
 | patterns.cs:108:24:112:9 | ... switch { ... } | patterns.cs:108:24:108:31 | (..., ...) |
 | patterns.cs:115:20:120:9 | ... switch { ... } | patterns.cs:115:20:115:27 | (..., ...) |
 | patterns.cs:126:17:132:9 | ... switch { ... } | patterns.cs:126:17:126:17 | access to local variable s |
-| patterns.cs:136:17:141:13 | ... switch { ... } | patterns.cs:136:17:136:17 | access to parameter o |
+| patterns.cs:136:17:143:13 | ... switch { ... } | patterns.cs:136:17:136:17 | access to parameter o |
 switchExprCases
 | patterns.cs:101:13:101:40 | ... => ... | patterns.cs:101:13:101:17 | Int32 y | patterns.cs:101:34:101:40 | "large" |
 | patterns.cs:102:13:102:24 | ... => ... | patterns.cs:102:13:102:13 | _ | patterns.cs:102:18:102:24 | "small" |
@@ -19,6 +19,8 @@ switchExprCases
 | patterns.cs:138:17:138:50 | ... => ... | patterns.cs:138:17:138:17 | 1 | patterns.cs:138:22:138:50 | throw ... |
 | patterns.cs:139:17:139:22 | ... => ... | patterns.cs:139:17:139:17 | 2 | patterns.cs:139:22:139:22 | 3 |
 | patterns.cs:140:17:140:42 | ... => ... | patterns.cs:140:17:140:24 | Object y | patterns.cs:140:42:140:42 | 4 |
+| patterns.cs:141:17:141:29 | ... => ... | patterns.cs:141:17:141:22 | access to type String | patterns.cs:141:29:141:29 | 5 |
+| patterns.cs:142:17:142:41 | ... => ... | patterns.cs:142:17:142:36 | { ... } | patterns.cs:142:41:142:41 | 6 |
 switchFilters
 | patterns.cs:101:13:101:40 | ... => ... | patterns.cs:101:24:101:29 | ... > ... |
 | patterns.cs:128:13:128:49 | ... => ... | patterns.cs:128:40:128:44 | ... > ... |
@@ -39,6 +41,7 @@ propertyPatterns
 | patterns.cs:128:22:128:33 | { ... } |
 | patterns.cs:129:22:129:30 | { ... } |
 | patterns.cs:140:36:140:37 | { ... } |
+| patterns.cs:142:26:142:34 | { ... } |
 propertyPatternChild
 | patterns.cs:13:27:13:38 | { ... } | 0 | patterns.cs:13:32:13:36 | Int32 x |
 | patterns.cs:22:27:22:53 | { ... } | 0 | patterns.cs:22:31:22:32 | 12 |
@@ -54,6 +57,7 @@ propertyPatternChild
 | patterns.cs:70:27:70:35 | { ... } | 0 | patterns.cs:70:32:70:33 | 10 |
 | patterns.cs:128:22:128:33 | { ... } | 0 | patterns.cs:128:27:128:31 | Int32 x |
 | patterns.cs:129:22:129:30 | { ... } | 0 | patterns.cs:129:27:129:28 | 10 |
+| patterns.cs:142:26:142:34 | { ... } | 0 | patterns.cs:142:31:142:32 | 10 |
 positionalPatterns
 | patterns.cs:57:18:57:23 | ( ... ) | patterns.cs:57:18:57:23 | { ... } | 0 | patterns.cs:57:19:57:19 | 1 |
 | patterns.cs:57:18:57:23 | ( ... ) | patterns.cs:57:18:57:23 | { ... } | 1 | patterns.cs:57:22:57:22 | 2 |
@@ -145,6 +149,7 @@ recursivePatterns
 | patterns.cs:129:13:129:33 | { ... } |
 | patterns.cs:130:13:130:18 | { ... } |
 | patterns.cs:140:36:140:37 | { ... } |
+| patterns.cs:142:17:142:36 | { ... } |
 discards
 | patterns.cs:27:51:27:51 | _ |
 | patterns.cs:94:22:94:22 | _ |
@@ -181,3 +186,4 @@ labeledPatternExpr
 | patterns.cs:70:32:70:33 | 10 | X |
 | patterns.cs:128:27:128:31 | Int32 x | X |
 | patterns.cs:129:27:129:28 | 10 | X |
+| patterns.cs:142:31:142:32 | 10 | X |
diff --git a/csharp/ql/test/library-tests/csharp8/patterns.ql b/csharp/ql/test/library-tests/csharp8/patterns.ql
index cf49ebc9e4ce..0a726c6bd496 100644
--- a/csharp/ql/test/library-tests/csharp8/patterns.ql
+++ b/csharp/ql/test/library-tests/csharp8/patterns.ql
@@ -66,6 +66,4 @@ query predicate isRecursivePatternExprWithDecl(
   decl = expr.getRecursivePattern().getVariableDeclExpr()
 }
 
-query predicate labeledPatternExpr(LabeledPatternExpr e, string s) {
-  s = e.getLabel()
-}
+query predicate labeledPatternExpr(LabeledPatternExpr e, string s) { s = e.getLabel() }
diff --git a/csharp/ql/test/library-tests/csharp8/ranges.ql b/csharp/ql/test/library-tests/csharp8/ranges.ql
index e6a9bf454f24..9cd0c8868d63 100644
--- a/csharp/ql/test/library-tests/csharp8/ranges.ql
+++ b/csharp/ql/test/library-tests/csharp8/ranges.ql
@@ -11,7 +11,7 @@ Expr stripConversions(Expr expr) {
   if getConversion(expr, _) then getConversion(expr, result) else result = expr
 }
 
-query predicate indexes(IndexExpr e, Expr c) { c = e.getExpr()  }
+query predicate indexes(IndexExpr e, Expr c) { c = e.getExpr() }
 
 query predicate ranges(RangeExpr e) { any() }
 
diff --git a/csharp/ql/test/library-tests/csharp8/switchexprcontrolflow.expected b/csharp/ql/test/library-tests/csharp8/switchexprcontrolflow.expected
index 87e546641bef..2f667b54767f 100644
--- a/csharp/ql/test/library-tests/csharp8/switchexprcontrolflow.expected
+++ b/csharp/ql/test/library-tests/csharp8/switchexprcontrolflow.expected
@@ -81,8 +81,8 @@
 | patterns.cs:119:33:119:38 | (..., ...) | patterns.cs:115:9:120:9 | ... = ... | semmle.label | successor |
 | patterns.cs:119:34:119:34 | 0 | patterns.cs:119:37:119:37 | 0 | semmle.label | successor |
 | patterns.cs:119:37:119:37 | 0 | patterns.cs:119:33:119:38 | (..., ...) | semmle.label | successor |
-| patterns.cs:123:10:123:21 | enter Expressions2 | patterns.cs:124:5:147:5 | {...} | semmle.label | successor |
-| patterns.cs:124:5:147:5 | {...} | patterns.cs:125:9:125:39 | ... ...; | semmle.label | successor |
+| patterns.cs:123:10:123:21 | enter Expressions2 | patterns.cs:124:5:149:5 | {...} | semmle.label | successor |
+| patterns.cs:124:5:149:5 | {...} | patterns.cs:125:9:125:39 | ... ...; | semmle.label | successor |
 | patterns.cs:125:9:125:39 | ... ...; | patterns.cs:125:17:125:38 | object creation of type MyStruct | semmle.label | successor |
 | patterns.cs:125:13:125:38 | MyStruct s = ... | patterns.cs:126:9:132:10 | ... ...; | semmle.label | successor |
 | patterns.cs:125:17:125:38 | object creation of type MyStruct | patterns.cs:125:36:125:36 | 0 | semmle.label | successor |
@@ -90,7 +90,7 @@
 | patterns.cs:125:32:125:36 | ... = ... | patterns.cs:125:30:125:38 | { ..., ... } | semmle.label | successor |
 | patterns.cs:125:36:125:36 | 0 | patterns.cs:125:32:125:36 | ... = ... | semmle.label | successor |
 | patterns.cs:126:9:132:10 | ... ...; | patterns.cs:126:17:132:9 | ... switch { ... } | semmle.label | successor |
-| patterns.cs:126:13:132:9 | Int32 r = ... | patterns.cs:134:9:146:9 | try {...} ... | semmle.label | successor |
+| patterns.cs:126:13:132:9 | Int32 r = ... | patterns.cs:134:9:148:9 | try {...} ... | semmle.label | successor |
 | patterns.cs:126:17:126:17 | access to local variable s | patterns.cs:128:13:128:49 | ... => ... | semmle.label | successor |
 | patterns.cs:126:17:132:9 | ... switch { ... } | patterns.cs:126:17:126:17 | access to local variable s | semmle.label | successor |
 | patterns.cs:128:13:128:33 | { ... } | patterns.cs:128:40:128:40 | access to local variable x | semmle.label | match |
@@ -123,38 +123,48 @@
 | patterns.cs:131:18:131:18 | Int32 x | patterns.cs:131:21:131:21 | _ | semmle.label | successor |
 | patterns.cs:131:21:131:21 | _ | patterns.cs:131:13:131:22 | (..., ...) | semmle.label | successor |
 | patterns.cs:131:27:131:27 | 3 | patterns.cs:126:13:132:9 | Int32 r = ... | semmle.label | successor |
-| patterns.cs:134:9:146:9 | try {...} ... | patterns.cs:135:9:142:9 | {...} | semmle.label | successor |
-| patterns.cs:135:9:142:9 | {...} | patterns.cs:136:13:141:14 | ...; | semmle.label | successor |
-| patterns.cs:136:13:141:13 | ... = ... | patterns.cs:123:10:123:21 | exit Expressions2 | semmle.label | successor |
-| patterns.cs:136:13:141:14 | ...; | patterns.cs:136:17:141:13 | ... switch { ... } | semmle.label | successor |
+| patterns.cs:134:9:148:9 | try {...} ... | patterns.cs:135:9:144:9 | {...} | semmle.label | successor |
+| patterns.cs:135:9:144:9 | {...} | patterns.cs:136:13:143:14 | ...; | semmle.label | successor |
+| patterns.cs:136:13:143:13 | ... = ... | patterns.cs:123:10:123:21 | exit Expressions2 | semmle.label | successor |
+| patterns.cs:136:13:143:14 | ...; | patterns.cs:136:17:143:13 | ... switch { ... } | semmle.label | successor |
 | patterns.cs:136:17:136:17 | access to parameter o | patterns.cs:138:17:138:50 | ... => ... | semmle.label | successor |
-| patterns.cs:136:17:141:13 | ... switch { ... } | patterns.cs:136:17:136:17 | access to parameter o | semmle.label | successor |
+| patterns.cs:136:17:143:13 | ... switch { ... } | patterns.cs:136:17:136:17 | access to parameter o | semmle.label | successor |
 | patterns.cs:138:17:138:17 | 1 | patterns.cs:138:28:138:50 | object creation of type ArgumentException | semmle.label | match |
 | patterns.cs:138:17:138:17 | 1 | patterns.cs:139:17:139:22 | ... => ... | semmle.label | no-match |
 | patterns.cs:138:17:138:50 | ... => ... | patterns.cs:138:17:138:17 | 1 | semmle.label | successor |
-| patterns.cs:138:22:138:50 | throw ... | patterns.cs:143:9:146:9 | [exception: ArgumentException] catch (...) {...} | semmle.label | exception(ArgumentException) |
+| patterns.cs:138:22:138:50 | throw ... | patterns.cs:145:9:148:9 | [exception: ArgumentException] catch (...) {...} | semmle.label | exception(ArgumentException) |
 | patterns.cs:138:28:138:50 | object creation of type ArgumentException | patterns.cs:138:22:138:50 | throw ... | semmle.label | successor |
-| patterns.cs:138:28:138:50 | object creation of type ArgumentException | patterns.cs:143:9:146:9 | [exception: Exception] catch (...) {...} | semmle.label | exception(Exception) |
+| patterns.cs:138:28:138:50 | object creation of type ArgumentException | patterns.cs:145:9:148:9 | [exception: Exception] catch (...) {...} | semmle.label | exception(Exception) |
 | patterns.cs:139:17:139:17 | 2 | patterns.cs:139:22:139:22 | 3 | semmle.label | match |
 | patterns.cs:139:17:139:17 | 2 | patterns.cs:140:17:140:42 | ... => ... | semmle.label | no-match |
 | patterns.cs:139:17:139:22 | ... => ... | patterns.cs:139:17:139:17 | 2 | semmle.label | successor |
-| patterns.cs:139:22:139:22 | 3 | patterns.cs:136:13:141:13 | ... = ... | semmle.label | successor |
+| patterns.cs:139:22:139:22 | 3 | patterns.cs:136:13:143:13 | ... = ... | semmle.label | successor |
 | patterns.cs:140:17:140:24 | Object y | patterns.cs:140:31:140:31 | access to local variable y | semmle.label | match |
-| patterns.cs:140:17:140:24 | Object y | patterns.cs:143:9:146:9 | [exception: InvalidOperationException] catch (...) {...} | semmle.label | exception(InvalidOperationException) |
+| patterns.cs:140:17:140:24 | Object y | patterns.cs:141:17:141:29 | ... => ... | semmle.label | no-match |
 | patterns.cs:140:17:140:42 | ... => ... | patterns.cs:140:17:140:24 | Object y | semmle.label | successor |
 | patterns.cs:140:31:140:31 | access to local variable y | patterns.cs:140:36:140:37 | { ... } | semmle.label | successor |
 | patterns.cs:140:31:140:37 | ... is ... | patterns.cs:140:42:140:42 | 4 | semmle.label | true |
-| patterns.cs:140:31:140:37 | ... is ... | patterns.cs:143:9:146:9 | [exception: InvalidOperationException] catch (...) {...} | semmle.label | exception(InvalidOperationException) |
+| patterns.cs:140:31:140:37 | ... is ... | patterns.cs:141:17:141:29 | ... => ... | semmle.label | false |
 | patterns.cs:140:36:140:37 | { ... } | patterns.cs:140:31:140:37 | ... is ... | semmle.label | successor |
 | patterns.cs:140:36:140:37 | { ... } | patterns.cs:140:36:140:37 | { ... } | semmle.label | successor |
-| patterns.cs:140:42:140:42 | 4 | patterns.cs:136:13:141:13 | ... = ... | semmle.label | successor |
-| patterns.cs:143:9:146:9 | [exception: ArgumentException] catch (...) {...} | patterns.cs:123:10:123:21 | exit Expressions2 | semmle.label | exception(ArgumentException) |
-| patterns.cs:143:9:146:9 | [exception: Exception] catch (...) {...} | patterns.cs:123:10:123:21 | exit Expressions2 | semmle.label | exception(Exception) |
-| patterns.cs:143:9:146:9 | [exception: Exception] catch (...) {...} | patterns.cs:143:41:143:42 | [exception: Exception] InvalidOperationException ex | semmle.label | match |
-| patterns.cs:143:9:146:9 | [exception: InvalidOperationException] catch (...) {...} | patterns.cs:143:41:143:42 | [exception: InvalidOperationException] InvalidOperationException ex | semmle.label | match |
-| patterns.cs:143:41:143:42 | [exception: Exception] InvalidOperationException ex | patterns.cs:144:9:146:9 | {...} | semmle.label | successor |
-| patterns.cs:143:41:143:42 | [exception: InvalidOperationException] InvalidOperationException ex | patterns.cs:144:9:146:9 | {...} | semmle.label | successor |
-| patterns.cs:144:9:146:9 | {...} | patterns.cs:145:13:145:51 | ...; | semmle.label | successor |
-| patterns.cs:145:13:145:50 | call to method WriteLine | patterns.cs:123:10:123:21 | exit Expressions2 | semmle.label | successor |
-| patterns.cs:145:13:145:51 | ...; | patterns.cs:145:31:145:49 | "Invalid operation" | semmle.label | successor |
-| patterns.cs:145:31:145:49 | "Invalid operation" | patterns.cs:145:13:145:50 | call to method WriteLine | semmle.label | successor |
+| patterns.cs:140:42:140:42 | 4 | patterns.cs:136:13:143:13 | ... = ... | semmle.label | successor |
+| patterns.cs:141:17:141:22 | access to type String | patterns.cs:141:29:141:29 | 5 | semmle.label | match |
+| patterns.cs:141:17:141:22 | access to type String | patterns.cs:142:17:142:41 | ... => ... | semmle.label | no-match |
+| patterns.cs:141:17:141:29 | ... => ... | patterns.cs:141:17:141:22 | access to type String | semmle.label | successor |
+| patterns.cs:141:29:141:29 | 5 | patterns.cs:136:13:143:13 | ... = ... | semmle.label | successor |
+| patterns.cs:142:17:142:36 | { ... } | patterns.cs:142:41:142:41 | 6 | semmle.label | match |
+| patterns.cs:142:17:142:36 | { ... } | patterns.cs:145:9:148:9 | [exception: InvalidOperationException] catch (...) {...} | semmle.label | exception(InvalidOperationException) |
+| patterns.cs:142:17:142:41 | ... => ... | patterns.cs:142:31:142:32 | 10 | semmle.label | successor |
+| patterns.cs:142:26:142:34 | { ... } | patterns.cs:142:17:142:36 | { ... } | semmle.label | successor |
+| patterns.cs:142:31:142:32 | 10 | patterns.cs:142:26:142:34 | { ... } | semmle.label | successor |
+| patterns.cs:142:41:142:41 | 6 | patterns.cs:136:13:143:13 | ... = ... | semmle.label | successor |
+| patterns.cs:145:9:148:9 | [exception: ArgumentException] catch (...) {...} | patterns.cs:123:10:123:21 | exit Expressions2 | semmle.label | exception(ArgumentException) |
+| patterns.cs:145:9:148:9 | [exception: Exception] catch (...) {...} | patterns.cs:123:10:123:21 | exit Expressions2 | semmle.label | exception(Exception) |
+| patterns.cs:145:9:148:9 | [exception: Exception] catch (...) {...} | patterns.cs:145:41:145:42 | [exception: Exception] InvalidOperationException ex | semmle.label | match |
+| patterns.cs:145:9:148:9 | [exception: InvalidOperationException] catch (...) {...} | patterns.cs:145:41:145:42 | [exception: InvalidOperationException] InvalidOperationException ex | semmle.label | match |
+| patterns.cs:145:41:145:42 | [exception: Exception] InvalidOperationException ex | patterns.cs:146:9:148:9 | {...} | semmle.label | successor |
+| patterns.cs:145:41:145:42 | [exception: InvalidOperationException] InvalidOperationException ex | patterns.cs:146:9:148:9 | {...} | semmle.label | successor |
+| patterns.cs:146:9:148:9 | {...} | patterns.cs:147:13:147:51 | ...; | semmle.label | successor |
+| patterns.cs:147:13:147:50 | call to method WriteLine | patterns.cs:123:10:123:21 | exit Expressions2 | semmle.label | successor |
+| patterns.cs:147:13:147:51 | ...; | patterns.cs:147:31:147:49 | "Invalid operation" | semmle.label | successor |
+| patterns.cs:147:31:147:49 | "Invalid operation" | patterns.cs:147:13:147:50 | call to method WriteLine | semmle.label | successor |
diff --git a/csharp/ql/test/library-tests/dataflow/ssa/SsaCapturedVariableDef.ql b/csharp/ql/test/library-tests/dataflow/ssa/SsaCapturedVariableDef.ql
index c0a320803ca4..f5815998200c 100644
--- a/csharp/ql/test/library-tests/dataflow/ssa/SsaCapturedVariableDef.ql
+++ b/csharp/ql/test/library-tests/dataflow/ssa/SsaCapturedVariableDef.ql
@@ -1,6 +1,8 @@
 import csharp
 
-from string inout, Ssa::ExplicitDefinition def, Ssa::Definition targetDef, ControlFlow::Node call, boolean additionalCalls
+from
+  string inout, Ssa::ExplicitDefinition def, Ssa::Definition targetDef, ControlFlow::Node call,
+  boolean additionalCalls
 where
   inout = "in" and def.isCapturedVariableDefinitionFlowIn(targetDef, call, additionalCalls)
   or
diff --git a/csharp/upgrades/57331d90231fc8247d5a5197f4ac45d502708c6a/expr_parent.ql b/csharp/upgrades/57331d90231fc8247d5a5197f4ac45d502708c6a/expr_parent.ql
new file mode 100644
index 000000000000..26cec97398fa
--- /dev/null
+++ b/csharp/upgrades/57331d90231fc8247d5a5197f4ac45d502708c6a/expr_parent.ql
@@ -0,0 +1,47 @@
+class Expr extends @expr {
+  string toString() { none() }
+}
+
+class ControlFlowElement extends @control_flow_element {
+  string toString() { none() }
+}
+
+private predicate discardTypeCaseStmt(@case cs, @type_access_expr ta) {
+  expr_parent(ta, 1, cs) and
+  expr_parent(any(@discard_expr de), 0, cs)
+}
+
+private predicate expr_parent_adjusted(Expr child, int i, ControlFlowElement parent) {
+  if parent instanceof @is_expr
+  then
+    i = 0 and
+    expr_parent(child, i, parent)
+    or
+    // e.g. `x is string s` or `x is null`
+    i = 1 and
+    expr_parent(child, any(int j | j in [2 .. 3]), parent)
+    or
+    // e.g. `x is string`
+    i = 1 and
+    not expr_parent(_, any(int j | j in [2 .. 3]), parent) and
+    expr_parent(child, i, parent)
+  else
+    if parent instanceof @case
+    then
+      // e.g. `case string s:` or `case 5:`
+      i = 0 and
+      expr_parent(child, i, parent) and
+      not discardTypeCaseStmt(parent, _)
+      or
+      // e.g. `case string _`
+      i = 0 and
+      discardTypeCaseStmt(parent, child)
+      or
+      i = 1 and
+      expr_parent(child, 2, parent)
+    else expr_parent(child, i, parent)
+}
+
+from Expr child, int i, ControlFlowElement parent
+where expr_parent_adjusted(child, i, parent)
+select child, i, parent
diff --git a/csharp/upgrades/57331d90231fc8247d5a5197f4ac45d502708c6a/upgrade.properties b/csharp/upgrades/57331d90231fc8247d5a5197f4ac45d502708c6a/upgrade.properties
index 3b3e6bd45643..1afe9e4f31cd 100644
--- a/csharp/upgrades/57331d90231fc8247d5a5197f4ac45d502708c6a/upgrade.properties
+++ b/csharp/upgrades/57331d90231fc8247d5a5197f4ac45d502708c6a/upgrade.properties
@@ -1,2 +1,4 @@
 description: Add C#8 expression and union types supporting ranges, recursive patterns and switch expressions.
 compatibility: backwards
+
+expr_parent.rel: run expr_parent.qlo
\ No newline at end of file