exported declarations now don't take the exclusive slot

src/compiler/binder.ts

@@ -125,40 +125,47 @@ module ts {
         function declareModuleMember(node: Declaration, symbolKind: SymbolFlags, symbolExcludes: SymbolFlags) {
             // Exported module members are given 2 symbols: A local symbol that is classified with an ExportValue,
             // ExportType, or ExportContainer flag, and an associated export symbol with all the correct flags set
-            // on it. There are 2 main reasons:
-            //
-            //   1. We treat locals and exports of the same name as mutually exclusive within a container. 
-            //      That means the binder will issue a Duplicate Identifier error if you mix locals and exports
-            //      with the same name in the same container.
-            //      TODO: Make this a more specific error and decouple it from the exclusion logic.
+            // on it. Reasons:
+            //   1. During name resolution i.e for types we need to distingush local and exported symbols.
+            //      All members are added to the exported one so local should never be returned.
             //   2. When we checkIdentifier in the checker, we set its resolved symbol to the local symbol,
             //      but return the export symbol (by calling getExportSymbolOfValueSymbolIfExported). That way
             //      when the emitter comes back to it, it knows not to qualify the name if it was found in a containing scope.
+            // Exported members will share local symbol with non-exported members
             var exportKind = 0;
-            var exportExcludes = 0;
             if (symbolKind & SymbolFlags.Value) {
                 exportKind |= SymbolFlags.ExportValue;
-                exportExcludes |= SymbolFlags.Value;
             }
             if (symbolKind & SymbolFlags.Type) {
                 exportKind |= SymbolFlags.ExportType;
-                exportExcludes |= SymbolFlags.Type;
             }
             if (symbolKind & SymbolFlags.Namespace) {
                 exportKind |= SymbolFlags.ExportNamespace;
-                exportExcludes |= SymbolFlags.Namespace;
             }
             if (node.flags & NodeFlags.Export || (node.kind !== SyntaxKind.ImportDeclaration && isAmbientContext(container))) {
                 if (exportKind) {
-                    var local = declareSymbol(container.locals, undefined, node, exportKind, exportExcludes);
-                    local.exportSymbol = declareSymbol(container.symbol.exports, container.symbol, node, symbolKind, symbolExcludes);
+                    var exportSymbol = declareSymbol(container.symbol.exports, container.symbol, node, symbolKind, symbolExcludes);
+                    var localSymbol = declareSymbol(container.locals, undefined, node, exportKind, symbolExcludes);
+                    node.symbol = exportSymbol;
+                    // export function foo(); // 1
+                    // export function foo() {} // 2
+                    // at (1) we'll create two symbols: local and exported and link then together
+                    // at (2) the same symbols will be returned as exported and local.
+                    // make sure that local symbol is added to the list of local symbols just once.
+                    if (!localSymbol.exportSymbol) {
+                        if (!exportSymbol.localSymbols) {
+                            exportSymbol.localSymbols = [];
+                        }
+                        exportSymbol.localSymbols.push(localSymbol);
+                        localSymbol.exportSymbol = exportSymbol;
+                    }
                 }
                 else {
                     declareSymbol(container.symbol.exports, container.symbol, node, symbolKind, symbolExcludes);
                 }
             }
             else {
-                declareSymbol(container.locals, undefined, node, symbolKind, symbolExcludes | exportKind);
+                declareSymbol(container.locals, undefined, node, symbolKind, symbolExcludes);
             }
         }
 

src/compiler/diagnosticInformationMap.generated.ts

@@ -131,6 +131,7 @@ module ts {
         A_signature_with_an_implementation_cannot_use_a_string_literal_type: { code: 2163, category: DiagnosticCategory.Error, key: "A signature with an implementation cannot use a string literal type." },
         Interface_0_cannot_simultaneously_extend_types_1_and_2_Colon: { code: 2189, category: DiagnosticCategory.Error, key: "Interface '{0}' cannot simultaneously extend types '{1}' and '{2}':" },
         Initializer_of_parameter_0_cannot_reference_identifier_1_declared_after_it: { code: 2190, category: DiagnosticCategory.Error, key: "Initializer of parameter '{0}' cannot reference identifier '{1}' declared after it." },
+        All_declarations_of_merged_declaration_0_must_be_exported_or_not_exported: { code: 2192, category: DiagnosticCategory.Error, key: "All declarations of merged declaration '{0}' must be exported or not exported." },
         super_cannot_be_referenced_in_constructor_arguments: { code: 2193, category: DiagnosticCategory.Error, key: "'super' cannot be referenced in constructor arguments." },
         Return_type_of_constructor_signature_must_be_assignable_to_the_instance_type_of_the_class: { code: 2194, category: DiagnosticCategory.Error, key: "Return type of constructor signature must be assignable to the instance type of the class" },
         Ambient_external_module_declaration_cannot_specify_relative_module_name: { code: 2196, category: DiagnosticCategory.Error, key: "Ambient external module declaration cannot specify relative module name." },

src/compiler/diagnosticMessages.json

@@ -518,6 +518,10 @@
         "category": "Error",
         "code": 2190
     },
+    "All declarations of merged declaration '{0}' must be exported or not exported.": {
+        "category": "Error",
+        "code": 2192
+    },
     "'super' cannot be referenced in constructor arguments.":{
         "category": "Error",
         "code": 2193

src/compiler/types.ts

@@ -648,7 +648,6 @@ module ts {
         IndexSignature     = 0x00020000,  // Index signature
         TypeParameter      = 0x00040000,  // Type parameter
 
-        // Export markers (see comment in declareModuleMember in binder)
         ExportValue        = 0x00080000,  // Exported value marker
         ExportType         = 0x00100000,  // Exported type marker
         ExportNamespace    = 0x00200000,  // Exported namespace marker
@@ -707,7 +706,8 @@ module ts {
         exports?: SymbolTable;         // Module exports
         exportSymbol?: Symbol;         // Exported symbol associated with this symbol
         exportAssignSymbol?: Symbol;   // Symbol exported from external module
-        valueDeclaration?: Declaration // First value declaration of the symbol
+        valueDeclaration?: Declaration;// First value declaration of the symbol
+        localSymbols?: Symbol[];       // List of local symbols that contribute to the export symbol
     }
 
     export interface SymbolLinks {

tests/baselines/reference/anonymousModules.errors.txt

@@ -24,7 +24,7 @@
 
     	var bar = 2;
     	    ~~~
-!!! Duplicate identifier 'bar'.
+!!! All declarations of merged declaration 'bar' must be exported or not exported.
 
     	module {
     	       ~

tests/baselines/reference/duplicateSymbolsExportMatching.errors.txt

@@ -25,11 +25,11 @@
         interface I { }
         export interface I { } // error
                          ~
-!!! Duplicate identifier 'I'.
+!!! All declarations of merged declaration 'I' must be exported or not exported.
         export interface E { }
         interface E { } // error
                   ~
-!!! Duplicate identifier 'E'.
+!!! All declarations of merged declaration 'E' must be exported or not exported.
     }
 
     // Should report error only once for instantiated module
@@ -39,7 +39,7 @@
         }
         export module inst { // one error
                       ~~~~
-!!! Duplicate identifier 'inst'.
+!!! All declarations of merged declaration 'inst' must be exported or not exported.
             var t;
         }
     }
@@ -49,28 +49,28 @@
         var v: string;
         export var v: string; // one error (visibility)
                    ~
-!!! Duplicate identifier 'v'.
+!!! All declarations of merged declaration 'v' must be exported or not exported.
         var w: number;
         export var w: string; // two errors (visibility and type mismatch)
                    ~
-!!! Duplicate identifier 'w'.
+!!! All declarations of merged declaration 'w' must be exported or not exported.
     }
 
     module M {
         module F {
+               ~
+!!! A module declaration cannot be located prior to a class or function with which it is merged
             var t;
         }
         export function F() { } // Only one error for duplicate identifier (don't consider visibility)
-                        ~
-!!! Duplicate identifier 'F'.
     }
 
     module M {
         class C { }
         module C { }
         export module C { // Two visibility errors (one for the clodule symbol, and one for the merged container symbol)
                       ~
-!!! Duplicate identifier 'C'.
+!!! All declarations of merged declaration 'C' must be exported or not exported.
             var t;
         }
     }
@@ -79,4 +79,4 @@
     interface D { }
     export interface D { }
                      ~
-!!! Duplicate identifier 'D'.
+!!! All declarations of merged declaration 'D' must be exported or not exported.

tests/baselines/reference/functionOverloadErrors.errors.txt

@@ -1,4 +1,4 @@
-==== tests/cases/conformance/functions/functionOverloadErrors.ts (19 errors) ====
+==== tests/cases/conformance/functions/functionOverloadErrors.ts (14 errors) ====
     //Function overload signature with initializer
     function fn1(x = 3);
                  ~~~~~
@@ -86,26 +86,16 @@
     //Function overloads with differing export
     module M {
         export function fn1();
-        ~~~~~~~~~~~~~~~~~~~~~~
-!!! Function implementation expected.
+                        ~~~
+!!! Overload signatures must all be exported or not exported.
         function fn1(n: string);
-        ~~~~~~~~~~~~~~~~~~~~~~~~
-!!! Function implementation expected.
-                 ~~~
-!!! Duplicate identifier 'fn1'.
         function fn1() { } 
-                 ~~~
-!!! Duplicate identifier 'fn1'.
 
         function fn2(n: string);
-        ~~~~~~~~~~~~~~~~~~~~~~~~
-!!! Function implementation expected.
+                 ~~~
+!!! Overload signatures must all be exported or not exported.
         export function fn2();
-                        ~~~
-!!! Duplicate identifier 'fn2'.
         export function fn2() { } 
-                        ~~~
-!!! Duplicate identifier 'fn2'.
     }
 
     //Function overloads with differing ambience

tests/baselines/reference/multivar.errors.txt

@@ -22,7 +22,7 @@
         declare var d1, d2;
         var b2;
             ~~
-!!! Duplicate identifier 'b2'.
+!!! All declarations of merged declaration 'b2' must be exported or not exported.
 
         declare var v1;
     }

tests/baselines/reference/overloadModifiersMustAgree.errors.txt

@@ -1,4 +1,4 @@
-==== tests/cases/compiler/overloadModifiersMustAgree.ts (5 errors) ====
+==== tests/cases/compiler/overloadModifiersMustAgree.ts (4 errors) ====
     class baz {
         public foo();
                ~~~
@@ -10,10 +10,8 @@
                      ~~~
 !!! Overload signatures must all be ambient or non-ambient.
     export function bar(s: string);
-    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-!!! Function implementation expected.
                     ~~~
-!!! Duplicate identifier 'bar'.
+!!! Overload signatures must all be exported or not exported.
     function bar(s?: string) { }
 
     interface I {