Don't consider flow types as bindings

packages/babel-plugin-check-es2015-constants/test/fixtures/general/flow-declar/actual.js

@@ -0,0 +1,2 @@
+declare class foo {}
+const foo = 1;

packages/babel-plugin-check-es2015-constants/test/fixtures/general/flow-declar/expected.js

@@ -0,0 +1 @@
+var foo = 1;

packages/babel-plugin-check-es2015-constants/test/fixtures/general/flow-declar/options.json

@@ -0,0 +1,3 @@
+{
+  "plugins": ["check-es2015-constants", "transform-es2015-block-scoping", "transform-flow-strip-types"]
+}

packages/babel-traverse/src/scope/index.js

@@ -48,6 +48,9 @@ let collectorVisitor = {
     // this will be hit again once we traverse into it after this iteration
     if (path.isExportDeclaration() && path.get("declaration").isDeclaration()) return;
 
+    // Skip flow declarations
+    if (path.isFlow()) return;
+
     // we've ran into a declaration!
     path.scope.getFunctionParent().registerDeclaration(path);
   },