1340148 - Disallow function redeclarations at module top level.

2 files changed, 25 insertions, 5 deletions

diff --git a/js/src/frontend/NameAnalysisTypes.h b/js/src/frontend/NameAnalysisTypes.h
index b94ca6cc0..2d327c827 100644
--- a/js/src/frontend/NameAnalysisTypes.h
+++ b/js/src/frontend/NameAnalysisTypes.h
@@ -78,6 +78,7 @@ enum class DeclarationKind : uint8_t
     Const,
     Import,
     BodyLevelFunction,
+    ModuleBodyLevelFunction,
     LexicalFunction,
     VarForAnnexBLexicalFunction,
     SimpleCatchParameter,
@@ -95,6 +96,7 @@ DeclarationKindToBindingKind(DeclarationKind kind)
 
       case DeclarationKind::Var:
       case DeclarationKind::BodyLevelFunction:
+      case DeclarationKind::ModuleBodyLevelFunction:
       case DeclarationKind::VarForAnnexBLexicalFunction:
       case DeclarationKind::ForOfVar:
         return BindingKind::Var;
diff --git a/js/src/frontend/Parser.cpp b/js/src/frontend/Parser.cpp
index c96e8c065..d62a26f76 100644
--- a/js/src/frontend/Parser.cpp
+++ b/js/src/frontend/Parser.cpp
@@ -119,6 +119,7 @@ DeclarationKindString(DeclarationKind kind)
       case DeclarationKind::Import:
         return "import";
       case DeclarationKind::BodyLevelFunction:
+      case DeclarationKind::ModuleBodyLevelFunction:
       case DeclarationKind::LexicalFunction:
         return "function";
       case DeclarationKind::VarForAnnexBLexicalFunction:
@@ -1380,6 +1381,24 @@ Parser<ParseHandler>::noteDeclaredName(HandlePropertyName name, DeclarationKind
         break;
       }
 
+      case DeclarationKind::ModuleBodyLevelFunction: {
+          MOZ_ASSERT(pc->atModuleLevel());
+
+          AddDeclaredNamePtr p = pc->varScope().lookupDeclaredNameForAdd(name);
+          if (p) {
+              reportRedeclaration(name, p->value()->kind(), pos, p->value()->pos());
+              return false;
+          }
+
+          if (!pc->varScope().addDeclaredName(pc, p, name, kind, pos.begin))
+              return false;
+
+          // Body-level functions in modules are always closed over.
+          pc->varScope().lookupDeclaredName(name)->value()->setClosedOver();
+
+          break;
+      }
+
       case DeclarationKind::FormalParameter: {
         // It is an early error if any non-positional formal parameter name
         // (e.g., destructuring formal parameter) is duplicated.
@@ -3750,12 +3769,11 @@ Parser<ParseHandler>::functionStmt(uint32_t preludeStart, YieldHandling yieldHan
         if (!noteDeclaredName(name, DeclarationKind::LexicalFunction, pos()))
             return null();
     } else {
-        if (!noteDeclaredName(name, DeclarationKind::BodyLevelFunction, pos()))
+        DeclarationKind kind = pc->atModuleLevel()
+                               ? DeclarationKind::ModuleBodyLevelFunction
+                               : DeclarationKind::BodyLevelFunction;
+        if (!noteDeclaredName(name, kind, pos()))
             return null();
-
-        // Body-level functions in modules are always closed over.
-        if (pc->atModuleLevel())
-            pc->varScope().lookupDeclaredName(name)->value()->setClosedOver();
     }
 
     Node pn = handler.newFunctionStatement();