[[FIX]] Allow latedef in the initialiser of variable

Fixes #2628
jshint · Aug 23, 2015 · 18f8775 · 18f8775
1 parent c59ce02
commit 18f8775
Show file tree

Hide file tree

Showing 5 changed files with 74 additions and 51 deletions.
diff --git a/src/jshint.js b/src/jshint.js
@@ -3521,25 +3521,6 @@ var JSHINT = (function() {
         warning("E012", state.tokens.curr, state.tokens.curr.value);
       }
 
-      // absorb the assignment before processing the label so that use of the label
-      // can be detected as before declaration
-      if (state.tokens.next.id === "=") {
-        advance("=");
-        if (!prefix && state.tokens.next.id === "undefined") {
-          warning("W080", state.tokens.prev, state.tokens.prev.value);
-        }
-        if (!prefix && peek(0).id === "=" && state.tokens.next.identifier) {
-          warning("W120", state.tokens.next, state.tokens.next.value);
-        }
-        // don't accept `in` in expression if prefix is used for ForIn/Of loop.
-        value = expression(prefix ? 120 : 10);
-        if (lone) {
-          tokens[0].first = value;
-        } else {
-          destructuringPatternMatch(names, value);
-        }
-      }
-
       for (var t in tokens) {
         if (tokens.hasOwnProperty(t)) {
           t = tokens[t];
@@ -3561,6 +3542,23 @@ var JSHINT = (function() {
         }
       }
 
+      if (state.tokens.next.id === "=") {
+        advance("=");
+        if (!prefix && state.tokens.next.id === "undefined") {
+          warning("W080", state.tokens.prev, state.tokens.prev.value);
+        }
+        if (!prefix && peek(0).id === "=" && state.tokens.next.identifier) {
+          warning("W120", state.tokens.next, state.tokens.next.value);
+        }
+        // don't accept `in` in expression if prefix is used for ForIn/Of loop.
+        value = expression(prefix ? 120 : 10);
+        if (lone) {
+          tokens[0].first = value;
+        } else {
+          destructuringPatternMatch(names, value);
+        }
+      }
+
       statement.first = statement.first.concat(names);
 
       if (state.tokens.next.id !== ",") {
@@ -3614,32 +3612,6 @@ var JSHINT = (function() {
 
       this.first = this.first.concat(names);
 
-      // absorb the assignment before processing the label so that use of the label
-      // can be detected as before declaration
-      if (state.tokens.next.id === "=") {
-        state.nameStack.set(state.tokens.curr);
-
-        advance("=");
-        if (!prefix && report && !state.funct["(loopage)"] &&
-          state.tokens.next.id === "undefined") {
-          warning("W080", state.tokens.prev, state.tokens.prev.value);
-        }
-        if (peek(0).id === "=" && state.tokens.next.identifier) {
-          if (!prefix && report &&
-              !state.funct["(params)"] ||
-              state.funct["(params)"].indexOf(state.tokens.next.value) === -1) {
-            warning("W120", state.tokens.next, state.tokens.next.value);
-          }
-        }
-        // don't accept `in` in expression if prefix is used for ForIn/Of loop.
-        value = expression(prefix ? 120 : 10);
-        if (lone) {
-          tokens[0].first = value;
-        } else {
-          destructuringPatternMatch(names, value);
-        }
-      }
-
       for (var t in tokens) {
         if (tokens.hasOwnProperty(t)) {
           t = tokens[t];
@@ -3674,6 +3646,30 @@ var JSHINT = (function() {
         }
       }
 
+      if (state.tokens.next.id === "=") {
+        state.nameStack.set(state.tokens.curr);
+
+        advance("=");
+        if (!prefix && report && !state.funct["(loopage)"] &&
+          state.tokens.next.id === "undefined") {
+          warning("W080", state.tokens.prev, state.tokens.prev.value);
+        }
+        if (peek(0).id === "=" && state.tokens.next.identifier) {
+          if (!prefix && report &&
+              !state.funct["(params)"] ||
+              state.funct["(params)"].indexOf(state.tokens.next.value) === -1) {
+            warning("W120", state.tokens.next, state.tokens.next.value);
+          }
+        }
+        // don't accept `in` in expression if prefix is used for ForIn/Of loop.
+        value = expression(prefix ? 120 : 10);
+        if (lone) {
+          tokens[0].first = value;
+        } else {
+          destructuringPatternMatch(names, value);
+        }
+      }
+
       if (state.tokens.next.id !== ",") {
         break;
       }

diff --git a/src/scope-manager.js b/src/scope-manager.js
@@ -747,15 +747,16 @@ var scopeManager = function(state, predefined, exported, declared) {
       use: function(labelName, token) {
 
         // if resolves to current function params, then do not store usage just resolve
-        // this is because function(a) { var a = a; } will resolve to the param, not
+        // this is because function(a) { var a; a = a; } will resolve to the param, not
         // to the unset var
         // first check the param is used
         var paramScope = _currentFunctBody["(parent)"];
         if (paramScope && paramScope["(labels)"][labelName] &&
           paramScope["(labels)"][labelName]["(type)"] === "param") {
 
-          // then check its not used
-          if (!scopeManagerInst.funct.has(labelName, { excludeParams: true })) {
+          // then check its not declared by a block scope variable
+          if (!scopeManagerInst.funct.has(labelName,
+                { excludeParams: true, onlyBlockscoped: true })) {
             paramScope["(labels)"][labelName]["(unused)"] = false;
           }
         }

diff --git a/tests/unit/fixtures/latedef-esnext.js b/tests/unit/fixtures/latedef-esnext.js
@@ -53,3 +53,10 @@ function cg() {
     cj();
 }
 cg();
+let da = () => da;
+const db = () => db;
+let dc = {
+    dd() {
+        return dc;
+    }
+};
diff --git a/tests/unit/fixtures/latedef.js b/tests/unit/fixtures/latedef.js
@@ -19,3 +19,12 @@ function foo() {
     return 10;
   }
 }
+var a = function() {
+  return a;
+};
+var b = b;
+var c = {
+  d: function() {
+    return d;
+  }
+};
diff --git a/tests/unit/options.js b/tests/unit/options.js
@@ -736,11 +736,21 @@ exports.undef = function (test) {
 
   // block scope cannot use themselves in the declaration
   TestRun(test)
-    .addError(1, "'a' was used before it was declared, which is illegal for 'let' variables.")
-    .addError(2, "'b' was used before it was declared, which is illegal for 'const' variables.")
+    // JSHint does not currently enforce the correct temporal dead zone
+    // semantics in this case. Once this is fixed, the following errors
+    // should be thrown:
+    //.addError(1, "'a' was used before it was declared, which is illegal for 'let' variables.")
+    //.addError(2, "'b' was used before it was declared, which is illegal for 'const' variables.")
+    .addError(5, "'e' is already defined.")
     .test([
       'let a = a;',
-      'const b = b;'
+      'const b = b;',
+      'var c = c;',
+      'function f(e) {',
+      '  var e;',         // the var does not overwrite the param, the param is used
+      '  e = e || 2;',
+      '  return e;',
+      '}'
     ], { esnext: true, undef: true });
 
   // Regression test for GH-668.