Create the module scope as a function

Summary:
Currently, we do not correctly process declarations at the top level of
a module because the DeclCollector is only run on functions. This is a
problem for modules, because they are defined as a scope in a dummy
global function, which does not actually contain the AST for the
modules. So when the DeclCollector runs, the declarations in the module
scope cannot be reached.

Using a function also ensures that vars declared at the top level of a
module are not treated as global properties.

Reviewed By: tmikov

Differential Revision: D36231405

fbshipit-source-id: 20a16daa905fe84e659630dc3410d9245ecb1831

unsupported/juno/crates/juno/src/sema/resolver.rs

@@ -256,7 +256,7 @@ impl<'gc> Resolver<'gc, '_> {
         scope_node: &'gc Node<'gc>,
         f: F,
     ) -> R {
-        // New biding table scope.
+        // New binding table scope.
         self.binding_table.push_scope();
         // New lexical scope.
         let prev_scope = self.current_scope;
@@ -447,17 +447,20 @@ impl<'gc> Resolver<'gc, '_> {
                     pself.declare_known_globals(lock, *global.range());
                 }
 
-                pself.in_new_scope(lock, node, |pself| {
-                    // Search for "use strict".
-                    if find_use_strict(lock, &node_cast!(Node::Module, node).body).is_some() {
-                        pself
-                            .sem
-                            .function_mut(pself.function_context().func_id)
-                            .strict = true;
-                    }
+                // Create the module scope as a function.
+                pself.in_new_function(lock, node, |pself| {
+                    pself.in_new_scope(lock, node, |pself| {
+                        // Search for "use strict".
+                        if find_use_strict(lock, &node_cast!(Node::Module, node).body).is_some() {
+                            pself
+                                .sem
+                                .function_mut(pself.function_context().func_id)
+                                .strict = true;
+                        }
 
-                    pself.process_collected_declarations(lock, node);
-                    node.visit_children(lock, pself);
+                        pself.process_collected_declarations(lock, node);
+                        node.visit_children(lock, pself);
+                    })
                 });
             })
         });

unsupported/juno/lit/juno/sema/module-function-decl.js

@@ -0,0 +1,16 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+// RUN: %juno %s %s | %FileCheck %s --match-full-lines
+
+function foo(){
+    return 42;
+}
+
+// CHECK-LABEL: Module: {{.*}}/module-function-decl.js
+// CHECK: 1 declarations
+// CHECK: Decl#0 'foo' ScopedFunction NotSpecial

unsupported/juno/lit/juno/sema/module-var-decl.js

@@ -0,0 +1,14 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+// RUN: %juno %s %s | %FileCheck %s --match-full-lines
+
+var x = 5;
+
+// CHECK-LABEL: Module: {{.*}}/module-var-decl.js
+// CHECK: 1 declarations
+// CHECK: Decl#0 'x' Var NotSpecial