diff --git a/packages/babel-core/src/parse.js b/packages/babel-core/src/parse.js
index ef905efb1f..b3397a1a2e 100644
--- a/packages/babel-core/src/parse.js
+++ b/packages/babel-core/src/parse.js
@@ -24,8 +24,8 @@ type Parse = {
 
 export const parse: Parse = (function parse(code, opts, callback) {
   if (typeof opts === "function") {
-    opts = undefined;
     callback = opts;
+    opts = undefined;
   }
 
   // For backward-compat with Babel 7's early betas, we allow sync parsing when
diff --git a/packages/babel-core/src/transform-ast.js b/packages/babel-core/src/transform-ast.js
index 62cef671e3..101177dcec 100644
--- a/packages/babel-core/src/transform-ast.js
+++ b/packages/babel-core/src/transform-ast.js
@@ -31,8 +31,8 @@ export const transformFromAst: TransformFromAst = (function transformFromAst(
   callback,
 ) {
   if (typeof opts === "function") {
-    opts = undefined;
     callback = opts;
+    opts = undefined;
   }
 
   // For backward-compat with Babel 6, we allow sync transformation when
diff --git a/packages/babel-core/src/transform.js b/packages/babel-core/src/transform.js
index 11a8ad5c0c..4a2f0e5c16 100644
--- a/packages/babel-core/src/transform.js
+++ b/packages/babel-core/src/transform.js
@@ -18,8 +18,8 @@ type Transform = {
 
 export const transform: Transform = (function transform(code, opts, callback) {
   if (typeof opts === "function") {
-    opts = undefined;
     callback = opts;
+    opts = undefined;
   }
 
   // For backward-compat with Babel 6, we allow sync transformation when