Do not allow TypeCastExpressions w/o parens

packages/babel-parser/src/parser/expression.js

@@ -804,7 +804,7 @@ export default class ExpressionParser extends LValParser {
           this.state.yieldInPossibleArrowParameters = null;
           const params = [this.parseIdentifier()];
           this.expect(tt.arrow);
-          // let foo = bar => {};
+          // let foo = async bar => {};
           this.parseArrowExpression(node, params, true);
           this.state.yieldInPossibleArrowParameters = oldYield;
           return node;

packages/babel-parser/src/parser/lval.js

@@ -177,6 +177,7 @@ export default class LValParser extends NodeUtils {
 
   toReferencedList(
     exprList: $ReadOnlyArray<?Expression>,
+    isInParens?: boolean, // eslint-disable-line no-unused-vars
   ): $ReadOnlyArray<?Expression> {
     return exprList;
   }

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

@@ -1976,40 +1976,26 @@ export default (superClass: Class<Parser>): Class<Parser> =>
     // type casts that we've found that are illegal in this context
     toReferencedList(
       exprList: $ReadOnlyArray<?N.Expression>,
+      isInParens?: boolean,
     ): $ReadOnlyArray<?N.Expression> {
       for (let i = 0; i < exprList.length; i++) {
         const expr = exprList[i];
-        if (expr && expr._exprListItem && expr.type === "TypeCastExpression") {
-          this.raise(expr.start, "Unexpected type cast");
+        if (
+          expr &&
+          expr.type === "TypeCastExpression" &&
+          (!expr.extra || !expr.extra.parenthesized) &&
+          (exprList.length > 1 || !isInParens)
+        ) {
+          this.raise(
+            expr.typeAnnotation.start,
+            "The type cast expression is expected to be wrapped with parenthesis",
+          );
         }
       }
 
       return exprList;
     }
 
-    // parse an item inside a expression list eg. `(NODE, NODE)` where NODE represents
-    // the position where this function is called
-    parseExprListItem(
-      allowEmpty: ?boolean,
-      refShorthandDefaultPos: ?Pos,
-      refNeedsArrowPos: ?Pos,
-    ): ?N.Expression {
-      const container = this.startNode();
-      const node = super.parseExprListItem(
-        allowEmpty,
-        refShorthandDefaultPos,
-        refNeedsArrowPos,
-      );
-      if (this.match(tt.colon)) {
-        container._exprListItem = true;
-        container.expression = node;
-        container.typeAnnotation = this.flowParseTypeAnnotation();
-        return this.finishNode(container, "TypeCastExpression");
-      } else {
-        return node;
-      }
-    }
-
     checkLVal(
       expr: N.Expression,
       isBinding: ?boolean,

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

@@ -2151,6 +2151,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
 
     toReferencedList(
       exprList: $ReadOnlyArray<?N.Expression>,
+      isInParens?: boolean, // eslint-disable-line no-unused-vars
     ): $ReadOnlyArray<?N.Expression> {
       for (let i = 0; i < exprList.length; i++) {
         const expr = exprList[i];

packages/babel-parser/test/fixtures/flow/typecasts/fail-in-calls-with-one-arg/input.js

@@ -0,0 +1 @@
+funccall(b: string);

packages/babel-parser/test/fixtures/flow/typecasts/fail-in-calls-with-one-arg/options.json

@@ -0,0 +1,3 @@
+{
+  "throws": "The type cast expression is expected to be wrapped with parenthesis (1:10)"
+}

packages/babel-parser/test/fixtures/flow/typecasts/fail-in-calls/input.js

@@ -0,0 +1 @@
+funccall(a, b: string);

packages/babel-parser/test/fixtures/flow/typecasts/fail-in-calls/options.json

@@ -0,0 +1,3 @@
+{
+  "throws": "The type cast expression is expected to be wrapped with parenthesis (1:13)"
+}

packages/babel-parser/test/fixtures/flow/typecasts/fail-without-parens/input.js

@@ -0,0 +1 @@
+(A, B: T)

packages/babel-parser/test/fixtures/flow/typecasts/fail-without-parens/options.json

@@ -0,0 +1,3 @@
+{
+  "throws": "The type cast expression is expected to be wrapped with parenthesis (1:5)"
+}

scripts/tests/flow/flow_tests_whitelist.txt

@@ -31,7 +31,6 @@ types/annotations_in_comments_invalid/migrated_0003.js
 types/annotations/void_is_reserved_param.js
 types/member/reserved_words.js
 types/parameter_defaults/migrated_0032.js
-types/typecasts_invalid/migrated_0001.js
 class_method_kinds/polymorphic_getter.js
 numbers/underscored_bin.js
 numbers/underscored_float.js