From 746cc7a7ca254d3faa7c4514b105af3bcfcacd4c Mon Sep 17 00:00:00 2001
From: capu <hi@capu.tech>
Date: Tue, 28 Feb 2023 16:24:04 -0300
Subject: [PATCH] process variable definitions as import usages

---
 lib/rules/best-practises/no-unused-import.js  | 15 +++++++++--
 test/rules/best-practises/no-unused-import.js | 27 +++++++++++++++++++
 2 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/lib/rules/best-practises/no-unused-import.js b/lib/rules/best-practises/no-unused-import.js
index 50e29b84..991c6bc1 100644
--- a/lib/rules/best-practises/no-unused-import.js
+++ b/lib/rules/best-practises/no-unused-import.js
@@ -29,11 +29,22 @@ class NoUnusedImportsChecker extends BaseChecker {
     })
   }
 
+  VariableDeclaration(node) {
+    if (node.typeName.type === 'UserDefinedTypeName') {
+      const importedName = node.typeName.namePath.split('.')[0]
+      if (this.importedNames[importedName]) {
+        this.importedNames[importedName].used = true
+      } else {
+        throw new Error('imported name isnt registered')
+      }
+    }
+  }
+
   ContractDefinition(node) {
     node.baseContracts.forEach((inheritanceSpecifier) => {
       if (inheritanceSpecifier.baseName.type === 'UserDefinedTypeName') {
         if (!this.importedNames[inheritanceSpecifier.baseName.namePath]) {
-          throw new Error('contract name isnt registered')
+          throw new Error('imported name isnt registered')
         }
         this.importedNames[inheritanceSpecifier.baseName.namePath].used = true
       } else {
@@ -47,7 +58,7 @@ class NoUnusedImportsChecker extends BaseChecker {
     if (this.importedNames[name]) {
       this.importedNames[name].used = true
     } else {
-      throw new Error('library name isnt registered')
+      throw new Error('imported name isnt registered')
     }
   }
 
diff --git a/test/rules/best-practises/no-unused-import.js b/test/rules/best-practises/no-unused-import.js
index f0ce7c45..77c9ef92 100644
--- a/test/rules/best-practises/no-unused-import.js
+++ b/test/rules/best-practises/no-unused-import.js
@@ -39,6 +39,33 @@ describe('Linter - no-unused-import', () => {
     assertNoErrors(report)
   })
 
+  it('should not raise when contract name is used in a state variable declaration', () => {
+    const code = `import {A} from './A.sol'; contract B { A public statevar; }`
+
+    const report = linter.processStr(code, {
+      rules: { 'no-unused-import': 'error' },
+    })
+    assertNoErrors(report)
+  })
+
+  it('should not raise when an imported subtype is used in a state variable declaration', () => {
+    const code = `import {A} from './A.sol'; contract B { A.thing public statevar; }`
+
+    const report = linter.processStr(code, {
+      rules: { 'no-unused-import': 'error' },
+    })
+    assertNoErrors(report)
+  })
+
+  it('should not raise when one of the imported contracts types is used in a function parameter declaration', () => {
+    const code = `import {A} from './A.sol'; contract B { function (A.thing statevar) public {} }`
+
+    const report = linter.processStr(code, {
+      rules: { 'no-unused-import': 'error' },
+    })
+    assertNoErrors(report)
+  })
+
   it('should raise when some of the imported names are not used', () => {
     const code = `import {A, B} from './A.sol'; contract C is A {}`