feat(compiler): better warning for invalid expressions in function/browser mode

fix #1266

packages/compiler-core/src/transforms/vIf.ts

@@ -22,6 +22,7 @@ import {
 } from '../ast'
 import { createCompilerError, ErrorCodes } from '../errors'
 import { processExpression } from './transformExpression'
+import { validateBrowserExpression } from '../validateExpression'
 import {
   CREATE_BLOCK,
   FRAGMENT,
@@ -93,6 +94,10 @@ export function processIf(
     dir.exp = processExpression(dir.exp as SimpleExpressionNode, context)
   }
 
+  if (__DEV__ && __BROWSER__ && dir.exp) {
+    validateBrowserExpression(dir.exp as SimpleExpressionNode, context)
+  }
+
   if (dir.name === 'if') {
     const branch = createIfBranch(node, dir)
     const ifNode: IfNode = {