Fixed false negatives for props in template in `vue/no-unused-propert…

…ies` (#2435)

lib/rules/no-unused-properties.js

@@ -233,6 +233,8 @@ module.exports = {
     const deepData = Boolean(options.deepData)
     const ignorePublicMembers = Boolean(options.ignorePublicMembers)
     const unreferencedOptions = new Set(options.unreferencedOptions || [])
+    /** @type {null | Pattern} */
+    let propsReferencePattern = null
 
     const propertyReferenceExtractor = definePropertyReferenceExtractor(
       context,
@@ -332,8 +334,9 @@ module.exports = {
 
         for (const property of container.properties) {
           if (
-            property.groupName === 'props' &&
-            propertyReferencesForProps.hasProperty(property.name)
+            (property.groupName === 'props' &&
+              propertyReferencesForProps.hasProperty(property.name)) ||
+            propertyReferences.hasProperty('$props')
           ) {
             // used props
             continue
@@ -369,6 +372,7 @@ module.exports = {
             }
             continue
           }
+
           context.report({
             node: property.node,
             messageId: 'unused',
@@ -450,9 +454,9 @@ module.exports = {
             return
           }
 
-          const pattern = target.parent.id
+          propsReferencePattern = target.parent.id
           const propertyReferences =
-            propertyReferenceExtractor.extractFromPattern(pattern)
+            propertyReferenceExtractor.extractFromPattern(propsReferencePattern)
           container.propertyReferencesForProps.push(propertyReferences)
         },
         onDefineModelEnter(node, model) {
@@ -709,9 +713,26 @@ module.exports = {
        * @param {VExpressionContainer} node
        */
       VExpressionContainer(node) {
-        templatePropertiesContainer.propertyReferences.push(
+        const property =
           propertyReferenceExtractor.extractFromVExpressionContainer(node)
-        )
+
+        templatePropertiesContainer.propertyReferences.push(property)
+
+        if (!propsReferencePattern) {
+          return
+        }
+
+        // props.prop in template
+        for (const key of property.allProperties().keys()) {
+          if (
+            propsReferencePattern.type === 'Identifier' &&
+            propsReferencePattern.name === key
+          ) {
+            templatePropertiesContainer.propertyReferences.push(
+              property.getNest(key)
+            )
+          }
+        }
       },
       /**
        * @param {VAttribute} node

tests/lib/rules/no-unused-properties.js

@@ -718,6 +718,20 @@ tester.run('no-unused-properties', rule, {
         </script>
       `
     },
+    // a property used as a template $props expression
+    {
+      filename: 'test.vue',
+      code: `
+        <template>
+          <div>{{ $props }}</div>
+        </template>
+        <script>
+          export default {
+            props: ['count']
+          }
+        </script>
+      `
+    },
 
     // properties used in a template expression
     {
@@ -910,6 +924,20 @@ tester.run('no-unused-properties', rule, {
         </script>
       `
     },
+    // a property used in v-on as $props expression
+    {
+      filename: 'test.vue',
+      code: `
+        <template>
+          <button @click="alert($props)" />
+        </template>
+        <script>
+          export default {
+            props: ['count']
+          };
+        </script>
+      `
+    },
 
     // data used in a script expression
     {
@@ -2452,6 +2480,48 @@ tester.run('no-unused-properties', rule, {
         {{ foo }}
       </template>
       `
+    },
+
+    // props.prop in template
+    {
+      filename: 'test.vue',
+      code: `
+      <template>
+        {{props}}
+      </template>
+      <script setup>
+      const props = defineProps(['a', 'b', 'c'])
+      </script>`
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <template>
+        {{props.a}}
+      </template>
+      <script setup>
+      const props = defineProps(['a'])
+      </script>`
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <template>
+        {{foo.a}}
+      </template>
+      <script setup>
+      const foo = defineProps(['a'])
+      </script>`
+    },
+    {
+      code: `
+      <script setup lang="ts">
+      const props = defineProps<{ foo: string, bar: string }>()
+      </script>
+      <template>
+      {{ props.foo }}{{ bar }}
+      </template>`,
+      ...getTypeScriptFixtureTestOptions()
     }
   ],
   invalid: [
@@ -4619,6 +4689,57 @@ tester.run('no-unused-properties', rule, {
           line: 6
         }
       ]
+    },
+
+    // a property used as a template $props member expression
+    {
+      filename: 'test.vue',
+      code: `
+        <template>
+          <div>{{ $props.foo }}</div>
+        </template>
+        <script>
+          export default {
+            props: ['foo', 'bar']
+          }
+        </script>
+      `,
+      errors: ["'bar' of property found, but never used."]
+    },
+
+    // props.prop in template
+    {
+      filename: 'test.vue',
+      code: `
+      <template>
+        {{props.a}}
+      </template>
+      <script setup>
+      const props = defineProps(['a', 'b'])
+      </script>`,
+      errors: ["'b' of property found, but never used."]
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <template>
+        {{foo.a}}
+      </template>
+      <script setup>
+      const foo = defineProps(['a', 'b'])
+      </script>`,
+      errors: ["'b' of property found, but never used."]
+    },
+    {
+      code: `
+      <script setup lang="ts">
+      const props = defineProps<{ foo: string, bar: string, baz: string }>()
+      </script>
+      <template>
+      {{ props.foo }}{{ bar }}
+      </template>`,
+      errors: ["'baz' of property found, but never used."],
+      ...getTypeScriptFixtureTestOptions()
     }
   ]
 })