Pass assumptions set in presets to plugins (#13321)

packages/babel-core/src/config/full.ts

@@ -68,10 +68,9 @@ export default gensync<(inputOpts: unknown) => ResolvedConfig | null>(
       throw new Error("Assertion failure - plugins and presets exist");
     }
 
-    const pluginContext: Context.FullPlugin = {
+    const presetContext: Context.FullPreset = {
       ...context,
       targets: options.targets,
-      assumptions: options.assumptions ?? {},
     };
 
     const toDescriptor = (item: PluginItem) => {
@@ -110,7 +109,7 @@ export default gensync<(inputOpts: unknown) => ResolvedConfig | null>(
                 presets.push({
                   preset: yield* loadPresetDescriptor(
                     descriptor,
-                    pluginContext,
+                    presetContext,
                   ),
                   pass: [],
                 });
@@ -118,7 +117,7 @@ export default gensync<(inputOpts: unknown) => ResolvedConfig | null>(
                 presets.unshift({
                   preset: yield* loadPresetDescriptor(
                     descriptor,
-                    pluginContext,
+                    presetContext,
                   ),
                   pass: pluginDescriptorsPass,
                 });
@@ -168,6 +167,11 @@ export default gensync<(inputOpts: unknown) => ResolvedConfig | null>(
     const opts: any = optionDefaults;
     mergeOptions(opts, options);
 
+    const pluginContext: Context.FullPlugin = {
+      ...presetContext,
+      assumptions: opts.assumptions ?? {},
+    };
+
     yield* enhanceError(context, function* loadPluginDescriptors() {
       pluginDescriptorsByPass[0].unshift(...initialPluginsDescriptors);