Unified: Synthesize implicit Swift initializers

unified/extractor/src/languages/swift/swift.rs

@@ -72,6 +72,23 @@ fn chained_modifier(ctx: &mut yeast::build::BuildCtx<'_, SwiftContext>) -> Optio
     }
 }
 
+fn implicit_parameterless_initializer(
+    ctx: &mut yeast::build::BuildCtx<'_, SwiftContext>,
+    members: &[yeast::Id],
+) -> Option<yeast::Id> {
+    let has_explicit_initializer = members.iter().any(|member| {
+        ctx.ast
+            .get_node(*member)
+            .is_some_and(|node| node.kind_name() == "constructor_declaration")
+    });
+    (!has_explicit_initializer).then(|| {
+        tree!((constructor_declaration
+            modifier: (modifier "generated")
+            name_node: (identifier "init")
+            body: (block)))
+    })
+}
+
 /// Combine a list of boolean sub-conditions into a single expression by
 /// left-folding with the infix `&&` operator. Used by control-flow
 /// rules (`if`, `guard`, `while`, `repeat-while`), which carry one or
@@ -1228,7 +1245,10 @@ fn translation_rules() -> Vec<Rule<SwiftContext>> {
             =>
             (equality_type_constraint left: {left} right: {right})
         ),
-        // Class declaration with body containing members
+        // Class declaration with body containing members. If the class has no
+        // explicit initializer, add a (possibly dead) implicit `init`. The implicit
+        // `init` is dead when the class inherits a constructor from its base class,
+        // which we cannot check in the extractor.
         rule!(
             (classDecl
                 classKeyword: @@kind
@@ -1241,15 +1261,19 @@ fn translation_rules() -> Vec<Rule<SwiftContext>> {
                 genericWhereClause: (genericWhereClause requirements: _* @declaration_constraints)?
                 memberBlock: (memberBlock members: _* @members))
             =>
-            (class_like_declaration
-                modifier: (modifier #{kind})
-                modifier: {mods}
-                name_node: (identifier #{name})
-                type_parameter: {params}
-                type_constraint: {parameter_constraints}
-                type_constraint: {declaration_constraints}
-                base_type: {bases.into_iter().map(|ty| tree!((base_type type: {ty})))}
-                member: {members})
+            class_like_declaration {
+                let implicit_initializer = implicit_parameterless_initializer(&mut ctx, &members);
+                tree!((class_like_declaration
+                    modifier: (modifier #{kind})
+                    modifier: {mods}
+                    name_node: (identifier #{name})
+                    type_parameter: {params}
+                    type_constraint: {parameter_constraints}
+                    type_constraint: {declaration_constraints}
+                    base_type: {bases.into_iter().map(|ty| tree!((base_type type: {ty})))}
+                    member: {members}
+                    member: {implicit_initializer}))
+            }
         ),
         // Enum class declaration: same as a regular class but with an enum body.
         rule!(
@@ -1274,7 +1298,8 @@ fn translation_rules() -> Vec<Rule<SwiftContext>> {
                 base_type: {bases.into_iter().map(|ty| tree!((base_type type: {ty})))}
                 member: {members})
         ),
-        // A `struct` declaration.
+        // A `struct` declaration, including an implicit parameter-less `init`
+        // when no explicit initializer is present.
         rule!(
             (structDecl
                 structKeyword: @@kind
@@ -1287,15 +1312,19 @@ fn translation_rules() -> Vec<Rule<SwiftContext>> {
                 genericWhereClause: (genericWhereClause requirements: _* @declaration_constraints)?
                 memberBlock: (memberBlock members: _* @members))
             =>
-            (class_like_declaration
-                modifier: (modifier #{kind})
-                modifier: {mods}
-                name_node: (identifier #{name})
-                type_parameter: {params}
-                type_constraint: {parameter_constraints}
-                type_constraint: {declaration_constraints}
-                base_type: {bases.into_iter().map(|ty| tree!((base_type type: {ty})))}
-                member: {members})
+            class_like_declaration {
+                let implicit_initializer = implicit_parameterless_initializer(&mut ctx, &members);
+                tree!((class_like_declaration
+                    modifier: (modifier #{kind})
+                    modifier: {mods}
+                    name_node: (identifier #{name})
+                    type_parameter: {params}
+                    type_constraint: {parameter_constraints}
+                    type_constraint: {declaration_constraints}
+                    base_type: {bases.into_iter().map(|ty| tree!((base_type type: {ty})))}
+                    member: {members}
+                    member: {implicit_initializer}))
+            }
         ),
         // Protocol declaration
         rule!(

unified/extractor/tests/corpus/swift/control-flow/discard-statement.output

@@ -80,3 +80,7 @@ top_level source="⟨body⟩"
               body:
                 block source="{\n    ⟨stmt⟩\n  }"
                   stmt: unsupported_node "discard self" source="discard self"
+            constructor_declaration source=""
+              modifier: modifier "generated" source=""
+              name_node: identifier "init" source=""
+              body: block source=""

unified/extractor/tests/corpus/swift/expressions/super-expression.output

@@ -157,6 +157,10 @@ top_level source="⟨body⟩"
             function_declaration source="func ⟨name_node⟩() ⟨body⟩"
               name_node: identifier "update" source="update"
               body: block "{}" source="{}"
+            constructor_declaration source=""
+              modifier: modifier "generated" source=""
+              name_node: identifier "init" source=""
+              body: block source=""
         class_like_declaration source="⟨modifier⟩ ⟨name_node⟩: ⟨base_type⟩ {\n  ⟨member⟩\n}"
           modifier: modifier "class" source="class"
           name_node: identifier "Derived" source="Derived"
@@ -182,3 +186,7 @@ top_level source="⟨body⟩"
                         member_access_expr source="⟨base⟩.⟨member_name_node⟩"
                           base: super_expr "super" source="super"
                           member_name_node: identifier "update" source="update"
+            constructor_declaration source=""
+              modifier: modifier "generated" source=""
+              name_node: identifier "init" source=""
+              body: block source=""

unified/extractor/tests/corpus/swift/functions/constructor-call-with-type-arguments.output

@@ -83,12 +83,22 @@ top_level source="⟨body⟩"
         class_like_declaration source="⟨modifier⟩ ⟨name_node⟩ {}"
           modifier: modifier "class" source="class"
           name_node: identifier "Foo" source="Foo"
+          member:
+            constructor_declaration source=""
+              modifier: modifier "generated" source=""
+              name_node: identifier "init" source=""
+              body: block source=""
         class_like_declaration source="⟨modifier⟩ ⟨name_node⟩<⟨type_parameter⟩> {}"
           modifier: modifier "class" source="class"
           name_node: identifier "C" source="C"
           type_parameter:
             type_parameter source="⟨name_node⟩"
               name_node: identifier "T" source="T"
+          member:
+            constructor_declaration source=""
+              modifier: modifier "generated" source=""
+              name_node: identifier "init" source=""
+              body: block source=""
         variable_declaration source="⟨modifier⟩ ⟨pattern⟩ = ⟨value⟩"
           modifier: modifier "let" source="let"
           pattern: identifier "x" source="x"

unified/extractor/tests/corpus/swift/types/class-function.output

@@ -55,3 +55,7 @@ top_level source="⟨body⟩"
               modifier: modifier "class" source="class"
               name_node: identifier "make" source="make"
               body: block "{}" source="{}"
+            constructor_declaration source=""
+              modifier: modifier "generated" source=""
+              name_node: identifier "init" source=""
+              body: block source=""

unified/extractor/tests/corpus/swift/types/class-inheritance.output

@@ -38,3 +38,8 @@ top_level source="⟨body⟩"
           base_type:
             base_type source="⟨type⟩"
               type: identifier "Animal" source="Animal"
+          member:
+            constructor_declaration source=""
+              modifier: modifier "generated" source=""
+              name_node: identifier "init" source=""
+              body: block source=""

unified/extractor/tests/corpus/swift/types/class-with-method.output

@@ -94,3 +94,7 @@ top_level source="⟨body⟩"
                       left: identifier "n" source="n"
                       operator: infix_operator "+=" source="+="
                       right: int_literal "1" source="1"
+            constructor_declaration source=""
+              modifier: modifier "generated" source=""
+              name_node: identifier "init" source=""
+              body: block source=""

unified/extractor/tests/corpus/swift/types/class-with-multiple-base-types.output

@@ -45,3 +45,8 @@ top_level source="⟨body⟩"
               type: identifier "Control" source="Control"
             base_type source="⟨type⟩"
               type: identifier "Drawable" source="Drawable"
+          member:
+            constructor_declaration source=""
+              modifier: modifier "generated" source=""
+              name_node: identifier "init" source=""
+              body: block source=""

unified/extractor/tests/corpus/swift/types/class-with-stored-properties.output

@@ -73,3 +73,7 @@ top_level source="⟨body⟩"
               modifier: modifier "var" source="var"
               pattern: identifier "y" source="y"
               type: identifier "Int" source="Int"
+            constructor_declaration source=""
+              modifier: modifier "generated" source=""
+              name_node: identifier "init" source=""
+              body: block source=""

unified/extractor/tests/corpus/swift/types/computed-property.output

@@ -127,3 +127,7 @@ top_level source="⟨body⟩"
                           left: identifier "w" source="w"
                           operator: infix_operator "*" source="*"
                           right: identifier "h" source="h"
+            constructor_declaration source=""
+              modifier: modifier "generated" source=""
+              name_node: identifier "init" source=""
+              body: block source=""

unified/extractor/tests/corpus/swift/types/conditional-compilation-in-class-body.output

@@ -84,4 +84,9 @@ top_level source="⟨body⟩"
         class_like_declaration source="⟨modifier⟩ ⟨name_node⟩ {\n⟨member⟩\n}"
           modifier: modifier "class" source="class"
           name_node: identifier "C" source="C"
-          member: unsupported_node "#if DEBUG\n    init(x: Int) {}\n    deinit {}\n#endif" source="#if DEBUG\n    init(x: Int) {}\n    deinit {}\n#endif"
+          member:
+            unsupported_node "#if DEBUG\n    init(x: Int) {}\n    deinit {}\n#endif" source="#if DEBUG\n    init(x: Int) {}\n    deinit {}\n#endif"
+            constructor_declaration source=""
+              modifier: modifier "generated" source=""
+              name_node: identifier "init" source=""
+              body: block source=""

unified/extractor/tests/corpus/swift/types/empty-class.output

@@ -27,3 +27,8 @@ top_level source="⟨body⟩"
         class_like_declaration source="⟨modifier⟩ ⟨name_node⟩ {}"
           modifier: modifier "class" source="class"
           name_node: identifier "Foo" source="Foo"
+          member:
+            constructor_declaration source=""
+              modifier: modifier "generated" source=""
+              name_node: identifier "init" source=""
+              body: block source=""

unified/extractor/tests/corpus/swift/types/generic-class-parameters-and-constraints.output

@@ -82,3 +82,8 @@ top_level source="⟨body⟩"
             equality_type_constraint source="⟨left⟩ == ⟨right⟩"
               left: identifier "U" source="U"
               right: identifier "T" source="T"
+          member:
+            constructor_declaration source=""
+              modifier: modifier "generated" source=""
+              name_node: identifier "init" source=""
+              body: block source=""

unified/extractor/tests/corpus/swift/types/noncopyable-type.output

@@ -65,3 +65,7 @@ top_level source="⟨body⟩"
               modifier: modifier "let" source="let"
               pattern: identifier "descriptor" source="descriptor"
               type: identifier "Int" source="Int"
+            constructor_declaration source=""
+              modifier: modifier "generated" source=""
+              name_node: identifier "init" source=""
+              body: block source=""

unified/extractor/tests/corpus/swift/types/property-with-getter-and-setter.output

@@ -140,3 +140,7 @@ top_level source="⟨body⟩"
                       left: identifier "_v" source="_v"
                       operator: infix_operator "=" source="="
                       right: identifier "newValue" source="newValue"
+            constructor_declaration source=""
+              modifier: modifier "generated" source=""
+              name_node: identifier "init" source=""
+              body: block source=""

unified/extractor/tests/corpus/swift/types/qualified-type.output

@@ -112,6 +112,19 @@ top_level source="⟨body⟩"
                 class_like_declaration source="⟨modifier⟩ ⟨name_node⟩ {}"
                   modifier: modifier "struct" source="struct"
                   name_node: identifier "Deep" source="Deep"
+                  member:
+                    constructor_declaration source=""
+                      modifier: modifier "generated" source=""
+                      name_node: identifier "init" source=""
+                      body: block source=""
+                constructor_declaration source=""
+                  modifier: modifier "generated" source=""
+                  name_node: identifier "init" source=""
+                  body: block source=""
+            constructor_declaration source=""
+              modifier: modifier "generated" source=""
+              name_node: identifier "init" source=""
+              body: block source=""
         variable_declaration source="⟨modifier⟩ ⟨pattern⟩: ⟨type⟩"
           modifier: modifier "let" source="let"
           pattern: identifier "value" source="value"

unified/extractor/tests/corpus/swift/types/static-function.output

@@ -55,3 +55,7 @@ top_level source="⟨body⟩"
               modifier: modifier "static" source="static"
               name_node: identifier "make" source="make"
               body: block "{}" source="{}"
+            constructor_declaration source=""
+              modifier: modifier "generated" source=""
+              name_node: identifier "init" source=""
+              body: block source=""

unified/extractor/tests/corpus/swift/types/struct.output

@@ -73,3 +73,7 @@ top_level source="⟨body⟩"
               modifier: modifier "let" source="let"
               pattern: identifier "y" source="y"
               type: identifier "Int" source="Int"
+            constructor_declaration source=""
+              modifier: modifier "generated" source=""
+              name_node: identifier "init" source=""
+              body: block source=""

unified/extractor/tests/corpus/swift/variables/property-with-willset-and-didset-observers.output

@@ -138,3 +138,7 @@ top_level source="⟨body⟩"
                       argument:
                         argument source="⟨value⟩"
                           value: identifier "oldValue" source="oldValue"
+            constructor_declaration source=""
+              modifier: modifier "generated" source=""
+              name_node: identifier "init" source=""
+              body: block source=""

unified/ql/lib/codeql/unified/internal/ControlFlowGraph.qll

@@ -31,6 +31,8 @@ module Ast implements AstSig<Location> {
     e instanceof Identifier and not e instanceof IdentifierExpr
     or
     e instanceof Operator
+    or
+    not e.fromSource()
   }
 
   AstNode getChild(AstNode n, int index) {

unified/ql/lib/codeql/unified/internal/FacadeAst.qll

@@ -17,8 +17,17 @@ module Unified {
     /** Gets the file containing this AST node. */
     File getFile() { result = this.getLocation().getFile() }
 
+    private predicate isGenerated() {
+      this.hasModifier("generated")
+      or
+      this.getParent().isGenerated()
+    }
+
     /** Holds if this AST node comes from ordinary source code. */
-    predicate fromSource() { this.getFile().fromSource() }
+    predicate fromSource() {
+      this.getFile().fromSource() and
+      not this.isGenerated()
+    }
 
     /** Holds if this AST node has a modifier with the given text. */
     predicate hasModifier(string text) {

unified/ql/test/library-tests/constructors/constructors.swift

@@ -0,0 +1,45 @@
+class C1 {}  // implicit parameterless `init`
+
+class C2: C1 {}  // inherits `init`
+
+class C3 {
+    init() {}
+}
+
+class C4: C3 {
+    init(_ x: Int) {
+        super.init()
+    }
+
+    override convenience init() {
+        self.init(0)
+    }
+}
+
+class C5: C4 {}  // inherits `init` and `convenience init`
+
+class C6<T1, T2> {
+    init(x: T1, y: T2) {}
+
+    private init(s: String) {}
+
+    convenience init(x: T1) {
+        fatalError("Convenience initializer not implemented")
+    }
+}
+
+class C7<T3, T4>: C6<T4, T3> {}  // inherits `init(x: T4, y: T3)` and `convenience init(x: T4)`
+
+class C8: C7<Int, String> {  // inherits `init(x: String, y: Int)`
+    convenience init(x: String) {
+        self.init(x: x, y: 0)
+    }
+}
+
+struct S1 {  // implicit `init(f1: Int = 0, f2: String, f4: Double)`
+    var f1: Int = 0
+    var f2: String
+    let f3: Bool = false
+    let f4: Double
+    static var f5: Float = 0.0
+}

unified/ql/test/library-tests/constructors/test.expected

@@ -0,0 +1,5 @@
+| constructors.swift:1:1:1:0 | init |
+| constructors.swift:3:1:3:0 | init |
+| constructors.swift:19:1:19:0 | init |
+| constructors.swift:31:1:31:0 | init |
+| constructors.swift:39:1:39:0 | init |

unified/ql/test/library-tests/constructors/test.ql

@@ -0,0 +1,6 @@
+import unified
+
+query predicate generatedConstructor(ConstructorDeclaration c) {
+  c = any(ClassLikeDeclaration cls | cls.fromSource()).getAMember() and
+  c.hasModifier("generated")
+}