makes the member accesses of parameters danger.

eslint · Jun 3, 2019 · 4e845fd · 4e845fd
1 parent e0d8a02
commit 4e845fd
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Showing 2 changed files with 14 additions and 3 deletions.
diff --git a/lib/rules/require-atomic-updates.js b/lib/rules/require-atomic-updates.js
@@ -55,14 +55,20 @@ function getWriteExpr(reference) {
 
 /**
  * Checks if an expression is a variable that can only be observed within the given function.
- * @param {escope.Variable} variable The variable to check
+ * @param {Variable|null} variable The variable to check
+ * @param {boolean} isMemberAccess If `true` then this is a member access.
  * @returns {boolean} `true` if the variable is local to the given function, and is never referenced in a closure.
  */
-function isLocalVariableWithoutEscape(variable) {
+function isLocalVariableWithoutEscape(variable, isMemberAccess) {
     if (!variable) {
         return false; // A global variable which was not defined.
     }
 
+    // If the reference is a property access and the variable is a parameter, it handles the variable is not local.
+    if (isMemberAccess && variable.defs.some(d => d.type === "Parameter")) {
+        return false;
+    }
+
     const functionScope = variable.scope.variableScope;
 
     return variable.references.every(reference =>
@@ -208,6 +214,7 @@ module.exports = {
                 const name = reference.identifier.name;
                 const variable = reference.resolved;
                 const writeExpr = getWriteExpr(reference);
+                const isMemberAccess = reference.identifier.parent.type === "MemberExpression";
 
                 // Add a fresh read variable.
                 if (reference.isRead() && !(writeExpr && writeExpr.parent.operator === "=")) {
@@ -220,7 +227,7 @@ module.exports = {
                  */
                 if (writeExpr &&
                     writeExpr.parent.right === writeExpr && // ← exclude variable declarations.
-                    !isLocalVariableWithoutEscape(variable)
+                    !isLocalVariableWithoutEscape(variable, isMemberAccess)
                 ) {
                     let refs = assignmentReferences.get(writeExpr);
 

diff --git a/tests/lib/rules/require-atomic-updates.js b/tests/lib/rules/require-atomic-updates.js
@@ -190,6 +190,10 @@ ruleTester.run("require-atomic-updates", rule, {
             code: "let foo; async function x() { foo += bar + await amount; }",
             errors: [VARIABLE_ERROR]
         },
+        {
+            code: "async function x() { let foo; bar(() => foo); foo += await amount; }",
+            errors: [VARIABLE_ERROR]
+        },
         {
             code: "let foo; function* x() { foo += yield baz }",
             errors: [VARIABLE_ERROR]