Merge pull request #7605 from michaelnebel/csharp/record-struct

C#: Support for record structs

Author: michaelnebel

csharp/extractor/Semmle.Extraction.CSharp/Entities/Modifier.cs

@@ -111,6 +111,9 @@ public static void ExtractModifiers(Context cx, TextWriter trapFile, IEntity key
                 if (nt is null)
                     throw new InternalError(symbol, "Symbol kind is inconsistent with its type");
 
+                if (nt.IsRecord)
+                    HasModifier(cx, trapFile, key, "record");
+
                 if (nt.TypeKind == TypeKind.Struct)
                 {
                     if (nt.IsReadOnly)

csharp/ql/lib/semmle/code/cil/Types.qll

@@ -61,7 +61,7 @@ class Class extends ValueOrRefType {
 }
 
 /** A `record`. */
-class Record extends Class {
+deprecated class Record extends Class {
   Record() { this.isRecord() }
 }
 

csharp/ql/lib/semmle/code/csharp/Type.qll

@@ -372,6 +372,8 @@ class ValueOrRefType extends DotNet::ValueOrRefType, Type, Attributable, @value_
     nested_types(this, _, result)
   }
 
+  override predicate isRecord() { this.hasModifier("record") }
+
   override string toString() { result = Type.super.toString() }
 }
 
@@ -449,6 +451,14 @@ class SimpleType extends ValueType, @simple_type {
   override SystemNamespace getDeclaringNamespace() { any() }
 }
 
+/**
+ * A `record` like type.
+ * This can be either a `class` or a `struct`.
+ */
+class RecordType extends ValueOrRefType {
+  RecordType() { this.isRecord() }
+}
+
 /**
  * The Boolean type, `bool`.
  */
@@ -711,6 +721,18 @@ class Struct extends ValueType, @struct_type {
   override string getAPrimaryQlClass() { result = "Struct" }
 }
 
+/**
+ * A `record struct`, for example
+ * ```csharp
+ * record struct RS {
+ *   ...
+ * }
+ * ```
+ */
+class RecordStruct extends RecordType, Struct {
+  override string getAPrimaryQlClass() { result = "RecordStruct" }
+}
+
 /**
  * A reference type.
  *
@@ -765,6 +787,16 @@ class Class extends RefType, @class_type {
   override string getAPrimaryQlClass() { result = "Class" }
 }
 
+/**
+ * DEPRECATED: Use `RecordClass` instead.
+ */
+deprecated class Record extends Class {
+  Record() { this.isRecord() }
+
+  /** Gets the clone method of this record. */
+  RecordCloneMethod getCloneMethod() { result = this.getAMember() }
+}
+
 /**
  * A `record`, for example
  *
@@ -774,13 +806,11 @@ class Class extends RefType, @class_type {
  * }
  * ```
  */
-class Record extends Class {
-  Record() { this.isRecord() }
-
+class RecordClass extends RecordType, Class {
   /** Gets the clone method of this record. */
   RecordCloneMethod getCloneMethod() { result = this.getAMember() }
 
-  override string getAPrimaryQlClass() { result = "Record" }
+  override string getAPrimaryQlClass() { result = "RecordClass" }
 }
 
 /**

csharp/ql/lib/semmle/code/csharp/dataflow/FlowSummary.qll

@@ -111,7 +111,7 @@ module SummaryComponentStack {
 class SummarizedCallable = Impl::Public::SummarizedCallable;
 
 private predicate recordConstructorFlow(Constructor c, int i, Property p) {
-  c = any(Record r).getAMember() and
+  c = any(RecordType r).getAMember() and
   exists(string name |
     c.getParameter(i).getName() = name and
     c.getDeclaringType().getAMember(name) = p

csharp/ql/lib/semmle/code/csharp/exprs/Expr.qll

@@ -1175,7 +1175,9 @@ class WithExpr extends Expr, @with_expr {
   Expr getExpr() { result = this.getChild(0) }
 
   /** Gets the clone method of the `record` that is targetted by this `with` expression. */
-  RecordCloneMethod getCloneMethod() { result = this.getExpr().getType().(Record).getCloneMethod() }
+  RecordCloneMethod getCloneMethod() {
+    result = this.getExpr().getType().(RecordClass).getCloneMethod()
+  }
 
   override string toString() { result = "... with { ... }" }
 

csharp/ql/test/library-tests/csharp10/RecordTypeSealedToString.cs

@@ -0,0 +1,12 @@
+using System;
+
+public record MyEntry(string Name, string Address)
+{
+    sealed public override string ToString() => $"{Name} lives at {Address}";
+};
+
+public record class MyClassRecord(DateTime stuff) { }
+
+public readonly record struct MyReadonlyRecordStruct(string Stuff) { }
+
+public record struct MyRecordStruct(int Stuff) { }

csharp/ql/test/library-tests/csharp10/RecordTypes.cs

@@ -1 +1 @@
-| RecordTypeSealedToString.cs:5:35:5:42 | ToString |
+| RecordTypes.cs:5:35:5:42 | ToString |

csharp/ql/test/library-tests/csharp10/recordTypeSealedToString.expected

@@ -0,0 +1,11 @@
+recordTypes
+| RecordTypes.cs:3:1:6:2 | MyEntry |
+| RecordTypes.cs:8:1:8:53 | MyClassRecord |
+| RecordTypes.cs:10:1:10:70 | MyReadonlyRecordStruct |
+| RecordTypes.cs:12:1:12:50 | MyRecordStruct |
+recordStructs
+| RecordTypes.cs:10:1:10:70 | MyReadonlyRecordStruct |
+| RecordTypes.cs:12:1:12:50 | MyRecordStruct |
+recordClass
+| RecordTypes.cs:3:1:6:2 | MyEntry |
+| RecordTypes.cs:8:1:8:53 | MyClassRecord |

csharp/ql/test/library-tests/csharp10/recordTypes.expected

@@ -0,0 +1,7 @@
+import csharp
+
+query predicate recordTypes(RecordType rt) { any() }
+
+query predicate recordStructs(RecordStruct rs) { any() }
+
+query predicate recordClass(RecordClass r) { any() }