Do not allow member expressions to start async arrows (#10332)

* Do not allow member expressions to start async arrows

* Boolean -> boolean

packages/babel-parser/src/plugins/flow.js

@@ -2634,7 +2634,6 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       startLoc: Position,
       noCalls: ?boolean,
       subscriptState: N.ParseSubscriptState,
-      maybeAsyncArrow: boolean,
     ): N.Expression {
       if (this.match(tt.questionDot) && this.isLookaheadRelational("<")) {
         this.expectPlugin("optionalChaining");
@@ -2687,7 +2686,6 @@ export default (superClass: Class<Parser>): Class<Parser> =>
         startLoc,
         noCalls,
         subscriptState,
-        maybeAsyncArrow,
       );
     }
 

packages/babel-parser/src/plugins/typescript/index.js

@@ -1568,7 +1568,6 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       startLoc: Position,
       noCalls: ?boolean,
       state: N.ParseSubscriptState,
-      maybeAsyncArrow: boolean,
     ): N.Expression {
       if (!this.hasPrecedingLineBreak() && this.match(tt.bang)) {
         this.state.exprAllowed = false;
@@ -1631,14 +1630,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
         if (result) return result;
       }
 
-      return super.parseSubscript(
-        base,
-        startPos,
-        startLoc,
-        noCalls,
-        state,
-        maybeAsyncArrow,
-      );
+      return super.parseSubscript(base, startPos, startLoc, noCalls, state);
     }
 
     parseNewArguments(node: N.NewExpression): void {