refactor(compiler-core): improve template type handling

packages/compiler-core/src/parse.ts

@@ -1,5 +1,5 @@
 import { ParserOptions } from './options'
-import { NO, isArray } from '@vue/shared'
+import { NO, isArray, makeMap } from '@vue/shared'
 import { ErrorCodes, createCompilerError, defaultOnError } from './errors'
 import {
   assert,
@@ -397,6 +397,10 @@ const enum TagType {
   End
 }
 
+const isSpecialTemplateDirective = /*#__PURE__*/ makeMap(
+  `if,else,else-if,for,slot`
+)
+
 /**
  * Parse a tag (E.g. `<div id=a>`) with that type (start tag or end tag).
  */
@@ -467,7 +471,14 @@ function parseTag(
 
     if (tag === 'slot') {
       tagType = ElementTypes.SLOT
-    } else if (tag === 'template') {
+    } else if (
+      tag === 'template' &&
+      props.some(p => {
+        return (
+          p.type === NodeTypes.DIRECTIVE && isSpecialTemplateDirective(p.name)
+        )
+      })
+    ) {
       tagType = ElementTypes.TEMPLATE
     }
   }

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

@@ -33,7 +33,6 @@ import {
 } from '../runtimeHelpers'
 import {
   getInnerRange,
-  isVSlot,
   toValidAssetId,
   findProp,
   isCoreComponent
@@ -48,12 +47,11 @@ const directiveImportMap = new WeakMap<DirectiveNode, symbol>()
 // generate a JavaScript AST for this element's codegen
 export const transformElement: NodeTransform = (node, context) => {
   if (
-    node.type !== NodeTypes.ELEMENT ||
-    // handled by transformSlotOutlet
-    node.tagType === ElementTypes.SLOT ||
-    // <template v-if/v-for> should have already been replaced
-    // <template v-slot> is handled by buildSlots
-    (node.tagType === ElementTypes.TEMPLATE && node.props.some(isVSlot))
+    !(
+      node.type === NodeTypes.ELEMENT &&
+      (node.tagType === ElementTypes.ELEMENT ||
+        node.tagType === ElementTypes.COMPONENT)
+    )
   ) {
     return
   }