Fix running flow on travis and update flow (#9128)

* Fix running flow on travis and update flow

- ensure bootstrap is run before running flow as we need some generated files for correctly doing typechecks
- ensure that we only ignore the build directory inside the babel folder as currently we ignore everything because travis checks out into ‘/home/travis/build/’

* Fix all flow errors

packages/babel-core/src/config/caching.js

@@ -43,6 +43,7 @@ export function makeWeakCache<
 >(
   handler: (ArgT, CacheConfigurator<SideChannel>) => ResultT,
 ): (ArgT, SideChannel) => ResultT {
+  // $FlowIssue https://github.com/facebook/flow/issues/4528
   return makeCachedFunction(new WeakMap(), handler);
 }
 
@@ -54,6 +55,7 @@ function makeCachedFunction<
   ArgT,
   ResultT,
   SideChannel,
+  // $FlowIssue https://github.com/facebook/flow/issues/4528
   Cache: CacheMap<ArgT, ResultT, SideChannel>,
 >(
   callCache: Cache,

packages/babel-core/src/config/validation/options.js

@@ -350,7 +350,7 @@ function validateNested(loc: NestingPath, opts: {}) {
       NONPRESET_VALIDATORS[key] ||
       BABELRC_VALIDATORS[key] ||
       ROOT_VALIDATORS[key] ||
-      throwUnknownError;
+      (throwUnknownError: Validator<void>);
 
     validator(optLoc, opts[key]);
   });

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

@@ -1759,7 +1759,7 @@ export default class ExpressionParser extends LValParser {
   parseArrowExpression(
     node: N.ArrowFunctionExpression,
     params?: ?(N.Expression[]),
-    isAsync?: boolean,
+    isAsync?: boolean = false,
   ): N.ArrowFunctionExpression {
     // if we got there, it's no more "yield in possible arrow parameters";
     // it's just "yield in arrow parameters"

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

@@ -896,9 +896,9 @@ export default class StatementParser extends ExpressionParser {
   parseFunction<T: N.NormalFunction>(
     node: T,
     isStatement: boolean,
-    allowExpressionBody?: boolean,
-    isAsync?: boolean,
-    optionalId?: boolean,
+    allowExpressionBody?: boolean = false,
+    isAsync?: boolean = false,
+    optionalId?: boolean = false,
   ): T {
     const oldInFunc = this.state.inFunction;
     const oldInMethod = this.state.inMethod;

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

@@ -300,7 +300,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
 
       if (node) {
         node.type = "Property";
-        if (node.kind === "method") node.kind = "init";
+        if (((node: any): N.ClassMethod).kind === "method") node.kind = "init";
         node.shorthand = false;
       }
 

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

@@ -1842,7 +1842,9 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       super.assertModuleNodeAllowed(node);
     }
 
-    parseExport(node: N.ExportNamedDeclaration): N.ExportNamedDeclaration {
+    parseExport(
+      node: N.ExportNamedDeclaration | N.ExportAllDeclaration,
+    ): N.ExportNamedDeclaration | N.ExportAllDeclaration {
       node = super.parseExport(node);
       if (
         node.type === "ExportNamedDeclaration" ||

packages/babel-parser/src/tokenizer/state.js

@@ -140,7 +140,10 @@ export default class State {
   // The first yield or await expression inside parenthesized expressions
   // and arrow function parameters. It is used to disallow yield and await in
   // arrow function parameters.
-  yieldOrAwaitInPossibleArrowParameters: ?N.YieldExpression;
+  yieldOrAwaitInPossibleArrowParameters:
+    | N.YieldExpression
+    | N.AwaitExpression
+    | null;
 
   // Token store.
   tokens: Array<Token | N.Comment>;

packages/babel-template/src/index.js

@@ -3,11 +3,11 @@
 import * as formatters from "./formatters";
 import createTemplateBuilder from "./builder";
 
-export const smart = createTemplateBuilder(formatters.smart);
-export const statement = createTemplateBuilder(formatters.statement);
-export const statements = createTemplateBuilder(formatters.statements);
-export const expression = createTemplateBuilder(formatters.expression);
-export const program = createTemplateBuilder(formatters.program);
+export const smart = createTemplateBuilder<*>(formatters.smart);
+export const statement = createTemplateBuilder<*>(formatters.statement);
+export const statements = createTemplateBuilder<*>(formatters.statements);
+export const expression = createTemplateBuilder<*>(formatters.expression);
+export const program = createTemplateBuilder<*>(formatters.program);
 
 type DefaultTemplateBuilder = typeof smart & {
   smart: typeof smart,