feat(compiler)!: interfaces, enums, and public classes must be defined at the top-level

docs/api/05-language-reference.md

@@ -1365,6 +1365,7 @@ If no catch block exists among caller functions, the program will terminate.
 Structs are loosely modeled after typed JSON literals in JavaScript.  
 Structs are defined with the `struct` keyword.  
 Structs are "bags" of immutable data.
+Structs must be defined at the top-level of a Wing file.
 
 Structs can only have fields of primitive types, preflight classes, and other structs.  
 Array, set, and map of above types is also allowed in struct field definition.  
@@ -1529,6 +1530,9 @@ Multiple inheritance is invalid and forbidden.
 Multiple implementations of various interfaces is allowed.  
 Multiple implementations of the same interface is invalid and forbidden.
 
+Classes can have an [access modifier](#15-access-modifiers-member-visibility) specifying whether it can be imported by other Wing source files.
+Classes can only be marked `pub` or `internal` if they are defined at the top-level of a Wing file.
+
 In methods if return type is missing, `: void` is assumed.
 
 #### Roadmap
@@ -1644,6 +1648,8 @@ of methods with different phases is not allowed as well.
 Interfaces represent a contract that a class must fulfill.
 Interfaces are defined with the `interface` keyword.
 Interfaces may be either preflight interfaces or inflight interfaces.
+Interfaces must be defined at the top-level of a Wing file.
+
 Preflight interfaces are defined in preflight scope and can contain both preflight and inflight methods.
 Only preflight classes may implement preflight interfaces.
 Inflight interfaces are either defined with the `inflight` modifier in preflight scope or simply defined in inflight scope.
@@ -1809,7 +1815,8 @@ Arrays are similar to dynamically sized arrays or vectors in other languages.
 
 Enumeration type (`enum`) is a type that groups a list of named constant members.
 Enumeration is defined by writing **enum**, followed by enumeration name and a
-list of comma-separated constants in a {}. 
+list of comma-separated constants in a {}.
+Enums must be defined at the top-level of a Wing file.
 Naming convention for enums is to use "TitleCase" for name and ALL_CAPS for members.
 
 > ```TS

examples/tests/invalid/class.test.w

@@ -226,3 +226,13 @@ class C13 {
   z: str;
   //^ Symbol "z" is already defined
 }
+
+if true {
+  pub class PublicClass {
+    // ^ public class "PublicClass" must be declared at the top-level of the file or marked private
+  }
+
+  internal class InternalClass {
+    // ^ internal class "PublicClass" must be declared at the top-level of the file or marked private
+  }
+}

examples/tests/invalid/enums.test.w

@@ -7,3 +7,10 @@ let four = SomeEnum.FOUR;
 
 let two = SomeEnum.TWO.TWO;
 // ERR                 ^^^ Property not found
+
+if true {
+  enum AnotherEnum {
+      // ^ Enums must be declared at the top-level of the file
+      FOUR, FIVE, SIX
+  }
+}

examples/tests/invalid/interface.test.w

@@ -66,4 +66,11 @@ inflight interface IInflightExtendsJsii extends jsii_fixture.ISomeInterface {
 // Inflight classes can't implement JSII interfaces
 inflight class CInflightImplJsii impl jsii_fixture.ISomeInterface {
   pub method(): void {}
-}
+}
+
+if true {
+  interface INestedInterface {
+    // ^ Interfaces must be declared at the top-level of the file
+    method(): void;
+  }
+}

examples/tests/valid/impl_interface.test.w

@@ -69,12 +69,11 @@ class Terrier extends Dog {
 
 let w: IAnimal = new Terrier();
 
-// interface inheriting the phase from the function it's inside
-// does it make sense to support this?
+inflight interface IDog {
+  bark(): void;
+} // All methods should be implicitly inflight
+
 let f = inflight () => {
-  interface IDog {
-    bark(): void;
-  } // All methods should be implicitly inflight
   class MyDog impl IDog {
     pub bark(): void {
       log("woof");
@@ -108,11 +107,6 @@ class ImplementInflightIfaceInPreflightClass impl IInflight {
   }
 }
 
-// Extend inflight interface in an inflight interface defined inflight
-inflight () => {
-  interface InflightIfaceDefinedInflight extends IInflight {}
-};
-
 // Extend inflight interface in an inflight interface defined preflight
 interface InflightIfaceDefinedPreflight extends IInflight {}
 
@@ -138,4 +132,4 @@ class ImplPreflightIfaceInPreflightClass impl IPreflight {
   pub method() {
     return;
   }
-}
+}

libs/wingc/src/type_check.rs

@@ -3902,7 +3902,7 @@ It should primarily be used in preflight or in inflights that are guaranteed to
 		if let Some(_) = env.parent {
 			self.spanned_error(
 				name,
-				format!("struct \"{name}\" must be declared at the top-level of a file"),
+				format!("struct \"{name}\" must be declared at the top-level of the file"),
 			);
 		}
 
@@ -3959,6 +3959,15 @@ It should primarily be used in preflight or in inflights that are guaranteed to
 			self.source_file.package.clone(),
 		);
 
+		// Interfaces can only be declared only at the top-level of a program
+		if let Some(_) = env.parent {
+			let name = &iface.name;
+			self.spanned_error(
+				name,
+				format!("interface \"{name}\" must be declared at the top-level of the file"),
+			);
+		}
+
 		// Collect types this interface extends
 		let extend_interfaces = iface
 			.extends
@@ -4010,6 +4019,15 @@ It should primarily be used in preflight or in inflights that are guaranteed to
 			docs: doc.as_ref().map_or(Docs::default(), |s| Docs::with_summary(s)),
 		}));
 
+		// Enums can only be declared only at the top-level of a program
+		if let Some(_) = env.parent {
+			let name = &enu.name;
+			self.spanned_error(
+				name,
+				format!("enum \"{name}\" must be declared at the top-level of the file"),
+			);
+		}
+
 		match env.define(
 			&enu.name,
 			SymbolKind::Type(enum_type_ref),
@@ -4481,6 +4499,19 @@ It should primarily be used in preflight or in inflights that are guaranteed to
 	fn type_check_class(&mut self, stmt: &Stmt, ast_class: &AstClass, env: &mut SymbolEnv) {
 		self.ctx.push_class(ast_class);
 
+		// Classes cannot be exported (via "pub" or "internal") if they are
+		// defined somewhere besides the top-level of the file.
+		if let Some(_) = env.parent {
+			let access = ast_class.access;
+			let name = &ast_class.name;
+			if access == AccessModifier::Public || access == AccessModifier::Internal {
+				self.spanned_error(
+					name,
+					format!("{access} class \"{name}\" must be declared at the top-level of the file or marked private"),
+				);
+			}
+		}
+
 		// preflight classes cannot be declared inside an inflight scope
 		// (the other way is okay)
 		if env.phase == Phase::Inflight && ast_class.phase == Phase::Preflight {

tools/hangar/__snapshots__/invalid.ts.snap

@@ -1046,6 +1046,20 @@ error: Expected type to be "str", but got "num" instead
 223 |     return 5;
     |            ^
 
+
+error: public class "PublicClass" must be declared at the top-level of the file or marked private
+    --> ../../../examples/tests/invalid/class.test.w:231:13
+    |
+231 |   pub class PublicClass {
+    |             ^^^^^^^^^^^
+
+
+error: internal class "InternalClass" must be declared at the top-level of the file or marked private
+    --> ../../../examples/tests/invalid/class.test.w:235:18
+    |
+235 |   internal class InternalClass {
+    |                  ^^^^^^^^^^^^^
+
 Tests 1 failed (1)
 Snapshots 1 skipped
 Test Files 1 failed (1)
@@ -1481,6 +1495,13 @@ error: Property not found
 8 | let two = SomeEnum.TWO.TWO;
   |                        ^^^
 
+
+error: enum "AnotherEnum" must be declared at the top-level of the file
+   --> ../../../examples/tests/invalid/enums.test.w:12:8
+   |
+12 |   enum AnotherEnum {
+   |        ^^^^^^^^^^^
+
 Tests 1 failed (1)
 Snapshots 1 skipped
 Test Files 1 failed (1)
@@ -2827,6 +2848,13 @@ error: Expected type to be "preflight (): void", but got "inflight (): void" ins
    |
    = hint: expected phase to be preflight, but got inflight instead
 
+
+error: interface "INestedInterface" must be declared at the top-level of the file
+   --> ../../../examples/tests/invalid/interface.test.w:72:13
+   |
+72 |   interface INestedInterface {
+   |             ^^^^^^^^^^^^^^^^
+
 Tests 1 failed (1)
 Snapshots 1 skipped
 Test Files 1 failed (1)
@@ -4861,14 +4889,14 @@ error: "noSuchField" is not a field of "SomeStruct1"
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 
-error: struct "PreflightStruct" must be declared at the top-level of a file
+error: struct "PreflightStruct" must be declared at the top-level of the file
    --> ../../../examples/tests/invalid/structs.test.w:51:10
    |
 51 |   struct PreflightStruct {
    |          ^^^^^^^^^^^^^^^
 
 
-error: struct "InflightStruct" must be declared at the top-level of a file
+error: struct "InflightStruct" must be declared at the top-level of the file
    --> ../../../examples/tests/invalid/structs.test.w:58:10
    |
 58 |   struct InflightStruct {

tools/hangar/__snapshots__/test_corpus/valid/impl_interface.test.w_compile_tf-aws.md

@@ -72,27 +72,6 @@ module.exports = function({  }) {
 //# sourceMappingURL=inflight.$Closure3-1.cjs.map
 ```
 
-## inflight.$Closure4-1.cjs
-```cjs
-"use strict";
-const $helpers = require("@winglang/sdk/lib/helpers");
-const $macros = require("@winglang/sdk/lib/macros");
-module.exports = function({  }) {
-  class $Closure4 {
-    constructor($args) {
-      const {  } = $args;
-      const $obj = (...args) => this.handle(...args);
-      Object.setPrototypeOf($obj, this);
-      return $obj;
-    }
-    async handle() {
-    }
-  }
-  return $Closure4;
-}
-//# sourceMappingURL=inflight.$Closure4-1.cjs.map
-```
-
 ## inflight.A-1.cjs
 ```cjs
 "use strict";
@@ -472,27 +451,6 @@ class $Root extends $stdlib.std.Resource {
         });
       }
     }
-    class $Closure4 extends $stdlib.std.AutoIdResource {
-      _id = $stdlib.core.closureId();
-      constructor($scope, $id, ) {
-        super($scope, $id);
-        $helpers.nodeof(this).hidden = true;
-      }
-      static _toInflightType() {
-        return `
-          require("${$helpers.normalPath(__dirname)}/inflight.$Closure4-1.cjs")({
-          })
-        `;
-      }
-      get _liftMap() {
-        return ({
-          "handle": [
-          ],
-          "$inflight_init": [
-          ],
-        });
-      }
-    }
     class ImplInflightIfaceInInflightClass extends $stdlib.std.Resource {
       constructor($scope, $id, ) {
         super($scope, $id);
@@ -512,8 +470,8 @@ class $Root extends $stdlib.std.Resource {
         });
       }
     }
-    if ($preflightTypesMap[11]) { throw new Error("ImplInflightIfaceInInflightClass is already in type map"); }
-    $preflightTypesMap[11] = ImplInflightIfaceInInflightClass;
+    if ($preflightTypesMap[10]) { throw new Error("ImplInflightIfaceInInflightClass is already in type map"); }
+    $preflightTypesMap[10] = ImplInflightIfaceInInflightClass;
     class ImplInflightIfaceInPreflightClass extends $stdlib.std.Resource {
       constructor($scope, $id, ) {
         super($scope, $id);
@@ -564,7 +522,6 @@ class $Root extends $stdlib.std.Resource {
     const z = new Dog(this, "Dog");
     const w = new Terrier(this, "Terrier");
     const f = new $Closure3(this, "$Closure3");
-    new $Closure4(this, "$Closure4");
   }
 }
 const $APP = $PlatformManager.createApp({ outdir: $outdir, name: "impl_interface.test", rootConstruct: $Root, isTestEnvironment: $wing_is_test, entrypointDir: process.env['WING_SOURCE_DIR'], rootId: process.env['WING_ROOT_ID'] });