[Compile Time Constant Extraction] Support for open existential expressions

Author: justin-s-kang

lib/ConstExtract/ConstExtract.cpp

@@ -355,6 +355,19 @@ extractCompileTimeValue(Expr *expr, const DeclContext *declContext) {
         }
       }
 
+      if (functionKind == ExprKind::FunctionConversion) {
+        auto functionConversionExpr = cast<FunctionConversionExpr>(callExpr->getFn());
+        if (functionConversionExpr->getSubExpr()->getKind() == ExprKind::DeclRef) {
+          auto declRefExpr = cast<DeclRefExpr>(functionConversionExpr->getSubExpr());
+          auto identifier =
+              declRefExpr->getDecl()->getName().getBaseIdentifier().str().str();
+
+          std::vector<FunctionParameter> parameters =
+              extractFunctionArguments(callExpr->getArgs(), declContext);
+          return std::make_shared<FunctionCallValue>(identifier, parameters);
+        }
+      }
+
       break;
     }
 
@@ -507,6 +520,12 @@ extractCompileTimeValue(Expr *expr, const DeclContext *declContext) {
       auto derivedExpr = cast<DerivedToBaseExpr>(expr);
       return extractCompileTimeValue(derivedExpr->getSubExpr(), declContext);
     }
+
+    case ExprKind::OpenExistential: {
+      auto openExistentialExpr = cast<OpenExistentialExpr>(expr);
+      return extractCompileTimeValue(openExistentialExpr->getExistentialValue(), declContext);
+    }
+
     default: {
       break;
     }

test/ConstExtraction/ExtractOpenExistential.swift

@@ -0,0 +1,70 @@
+// RUN: %empty-directory(%t)
+// RUN: echo "[MyProto]" > %t/protocols.json
+
+// RUN: %target-swift-frontend -typecheck -emit-const-values-path %t/ExtractOpenExistential.swiftconstvalues -const-gather-protocols-file %t/protocols.json -primary-file %s
+// RUN: cat %t/ExtractOpenExistential.swiftconstvalues 2>&1 | %FileCheck %s
+
+protocol MyProto {}
+
+protocol ExampleProtocol {
+    var protocolProperty: String { get }
+}
+
+struct ConcreteType: ExampleProtocol {
+    let protocolProperty: String = "Concrete implementation"
+}
+
+func useExistential(_ example: any ExampleProtocol) -> String {
+    return example.protocolProperty
+}
+
+public struct External: MyProto {
+    static let existentialValue = useExistential(ConcreteType())
+}
+
+
+// CHECK: [
+// CHECK-NEXT:   {
+// CHECK-NEXT:     "typeName": "ExtractOpenExistential.External",
+// CHECK-NEXT:     "mangledTypeName": "22ExtractOpenExistential8ExternalV",
+// CHECK-NEXT:     "kind": "struct",
+// CHECK-NEXT:     "file": "{{.*}}test{{/|\\\\}}ConstExtraction{{/|\\\\}}ExtractOpenExistential.swift",
+// CHECK-NEXT:     "line": 21,
+// CHECK-NEXT:     "conformances": [
+// CHECK-NEXT:       "ExtractOpenExistential.MyProto"
+// CHECK-NEXT:     ],
+// CHECK-NEXT:     "allConformances": [
+// CHECK-NEXT:       {
+// CHECK-NEXT:         "protocolName": "ExtractOpenExistential.MyProto"
+// CHECK-NEXT:         "conformanceDefiningModule": "ExtractOpenExistential"
+// CHECK-NEXT:       }
+// CHECK-NEXT:     ],
+// CHECK-NEXT:     "associatedTypeAliases": [],
+// CHECK-NEXT:     "properties": [
+// CHECK-NEXT:       {
+// CHECK-NEXT:         "label": "existentialValue",
+// CHECK-NEXT:         "type": "Swift.String",
+// CHECK-NEXT:         "mangledTypeName": "n/a - deprecated",
+// CHECK-NEXT:         "isStatic": "true",
+// CHECK-NEXT:         "isComputed": "false",
+// CHECK-NEXT:         "file": "{{.*}}test{{/|\\\\}}ConstExtraction{{/|\\\\}}ExtractOpenExistential.swift",
+// CHECK-NEXT:         "line": 22,
+// CHECK-NEXT:         "valueKind": "FunctionCall",
+// CHECK-NEXT:         "value": {
+// CHECK-NEXT:           "name": "useExistential",
+// CHECK-NEXT:           "arguments": [
+// CHECK-NEXT:             {
+// CHECK-NEXT:               "label": "",
+// CHECK-NEXT:               "type": "any ExtractOpenExistential.ExampleProtocol",
+// CHECK-NEXT:               "valueKind": "InitCall",
+// CHECK-NEXT:               "value": {
+// CHECK-NEXT:                 "type": "ExtractOpenExistential.ConcreteType",
+// CHECK-NEXT:                 "arguments": []
+// CHECK-NEXT:               }
+// CHECK-NEXT:             }
+// CHECK-NEXT:           ]
+// CHECK-NEXT:         }
+// CHECK-NEXT:       }
+// CHECK-NEXT:     ]
+// CHECK-NEXT:   }
+// CHECK-NEXT: ]