[[FIX]] latedef shouldn't warn when marking a var as exported

Fixes #2662

src/scope-manager.js

@@ -65,21 +65,6 @@ var scopeManager = function(state, predefined, exported, declared) {
     }
   }
 
-  function _addUsage(labelName, token) {
-
-    _setupUsages(labelName);
-
-    if (token) {
-      token["(function)"] = _currentFunctBody;
-      _current["(usages)"][labelName]["(tokens)"].push(token);
-    }
-  }
-
-  var exportedLabels = Object.keys(exported);
-  for (var i = 0; i < exportedLabels.length; i++) {
-    _addUsage(exportedLabels[i]);
-  }
-
   var _getUnusedOption = function(unused_opt) {
     if (unused_opt === undefined) {
       unused_opt = state.option.unused;
@@ -572,7 +557,30 @@ var scopeManager = function(state, predefined, exported, declared) {
     /**
      * for the exported options, indicating a variable is used outside the file
      */
-    addExported: _addUsage,
+    addExported: function(labelName) {
+      var globalLabels = _scopeStack[0]["(labels)"];
+      if (_.has(declared, labelName)) {
+        // remove the declared token, so we know it is used
+        delete declared[labelName];
+      } else if (_.has(globalLabels, labelName)) {
+        globalLabels[labelName]["(unused)"] = false;
+      } else {
+        for (var i = 1; i < _scopeStack.length; i++) {
+          var scope = _scopeStack[i];
+          // if `scope.(type)` is not defined, it is a block scope
+          if (!scope["(type)"]) {
+            if (_.has(scope["(labels)"], labelName) &&
+                !scope["(labels)"][labelName]["(blockscoped)"]) {
+              scope["(labels)"][labelName]["(unused)"] = false;
+              return;
+            }
+          } else {
+            break;
+          }
+        }
+        exported[labelName] = true;
+      }
+    },
 
     /**
      * Mark an indentifier as es6 module exported
@@ -593,6 +601,8 @@ var scopeManager = function(state, predefined, exported, declared) {
       var type  = opts.type;
       var token = opts.token;
       var isblockscoped = type === "let" || type === "const" || type === "class";
+      var isexported    = (isblockscoped ? _current : _currentFunctBody)["(type)"] === "global" &&
+                          _.has(exported, labelName);
 
       // outer shadow check (inner is only on non-block scoped)
       _checkOuterShadow(labelName, token, type);
@@ -632,7 +642,7 @@ var scopeManager = function(state, predefined, exported, declared) {
           }
         }
 
-        scopeManagerInst.block.add(labelName, type, token, true);
+        scopeManagerInst.block.add(labelName, type, token, !isexported);
 
       } else {
 
@@ -659,7 +669,7 @@ var scopeManager = function(state, predefined, exported, declared) {
           }
         }
 
-        scopeManagerInst.funct.add(labelName, type, token, true);
+        scopeManagerInst.funct.add(labelName, type, token, !isexported);
 
         if (_currentFunctBody["(type)"] === "global") {
           usedPredefinedAndGlobals[labelName] = marker;
@@ -765,7 +775,12 @@ var scopeManager = function(state, predefined, exported, declared) {
           token.ignoreUndef = true;
         }
 
-        _addUsage(labelName, token);
+        _setupUsages(labelName);
+
+        if (token) {
+          token["(function)"] = _currentFunctBody;
+          _current["(usages)"][labelName]["(tokens)"].push(token);
+        }
       },
 
       reassign: function(labelName, token) {

tests/unit/fixtures/exported.js

@@ -15,4 +15,20 @@ var unusedExpression = function () {};
 
 (function () {
   function cannotBeExported() {}
-}());
+}());
+
+var a, b;
+if (true) {
+  /* exported a */
+}
+if (true) {
+  for(var i = 0; i < 1; i++) {
+    // dont peek
+  }
+  /* exported b */
+}
+
+if (true) {
+  var c;
+}
+/* exported c */

tests/unit/options.js

@@ -259,6 +259,9 @@ exports.latedef = function (test) {
       .addError(48, "'ci' was used before it was defined.")
       .test(esnextSrc, {esnext: true, latedef: true});
 
+  TestRun(test, "shouldn't warn when marking a var as exported")
+    .test("var a;", { exported: ["a"], latedef: true });
+
   test.done();
 };
 
@@ -272,6 +275,9 @@ exports.latedefInline = function (test) {
     .addError(26, "Bad option value.")
     .test(src);
 
+  TestRun(test, "shouldn't warn when marking a var as exported")
+    .test("/*exported a*/var a;", { latedef: true });
+
   test.done();
 };
 

tests/unit/parser.js

@@ -1124,11 +1124,36 @@ exports.exported = function (test) {
   run.test(src, {unused: true }); // es5
   run.test(src, {esnext: true, unused: true });
   run.test(src, {moz: true, unused: true });
+  run.test(src, {unused: true, latedef: true});
 
-  run = TestRun(test)
+  TestRun(test)
     .addError(1, "'unused' is defined but never used.")
     .test("var unused = 1; var used = 2;", {exported: ["used"], unused: true});
 
+  TestRun(test, "exported vars aren't used before definition")
+    .test("var a;", {exported:["a"], latedef: true});
+
+  var code = [
+    "/* exported a, b */",
+    "if (true) {",
+    "  /* exported c, d */",
+    "  let a, c, e, g;",
+    "  const [b, d, f, h] = [];",
+    "  /* exported e, f */",
+    "}",
+    "/* exported g, h */"
+  ];
+  TestRun(test, "blockscoped variables")
+    .addError(4, "'a' is defined but never used.")
+    .addError(4, "'c' is defined but never used.")
+    .addError(4, "'e' is defined but never used.")
+    .addError(4, "'g' is defined but never used.")
+    .addError(5, "'b' is defined but never used.")
+    .addError(5, "'d' is defined but never used.")
+    .addError(5, "'f' is defined but never used.")
+    .addError(5, "'h' is defined but never used.")
+    .test(code, {esversion: 6, unused: true});
+
   test.done();
 };