From 5bf578935ccad043da106af3bbcc523f87c83dd5 Mon Sep 17 00:00:00 2001
From: Joe Hildebrand <joe-github@cursive.net>
Date: Sat, 17 Feb 2024 06:20:10 -0700
Subject: [PATCH] Add no-unused-rule processing for imports

---
 lib/rules/no-unused-rules.js       | 39 +++++++++++++++++++++
 src/rules/no-unused-rules.ts       | 44 ++++++++++++++++++++++++
 test/rules/no-unused-rules.test.js | 55 ++++++++++++++++++++++++++++++
 3 files changed, 138 insertions(+)

diff --git a/lib/rules/no-unused-rules.js b/lib/rules/no-unused-rules.js
index 25bd188..bca9b69 100644
--- a/lib/rules/no-unused-rules.js
+++ b/lib/rules/no-unused-rules.js
@@ -11,13 +11,36 @@ const rule = {
         },
         messages: {
             unused: "Rule '{{ name }}' is never used.",
+            unusedImport: "Library import '{{ name }}' is never used.",
         },
         schema: [],
     },
     create(context) {
+        const imports = new Map();
         const rules = new Map();
         const refs = new Set();
+        const importRefs = new Set();
         return (0, utils_1.makeListener)({
+            import_binding(node) {
+                if (node.binding.id) {
+                    imports.set(node.binding.id.value, node);
+                }
+            },
+            import_binding_all(node) {
+                if (node.binding.id) {
+                    imports.set(node.binding.id.value, node);
+                }
+            },
+            import_binding_default(node) {
+                if (node.binding.id) {
+                    imports.set(node.binding.id.value, node);
+                }
+            },
+            import_binding_rename(node) {
+                if (node.binding.id) {
+                    imports.set(node.binding.id.value, node);
+                }
+            },
             rule(node) {
                 if (rules.size === 0) {
                     // Default start rule counts as a reference.
@@ -28,9 +51,13 @@ const rule = {
             rule_ref(node) {
                 refs.add(node.name.value);
             },
+            library_ref(node) {
+                importRefs.add(node.library.value);
+            },
             "Program:exit": () => {
                 for (const name of refs) {
                     rules.delete(name);
+                    imports.delete(name);
                 }
                 for (const [name, r] of rules) {
                     context.report({
@@ -41,6 +68,18 @@ const rule = {
                         },
                     });
                 }
+                for (const name of importRefs) {
+                    imports.delete(name);
+                }
+                for (const [name, r] of imports) {
+                    context.report({
+                        node: (0, utils_1.n)(r),
+                        messageId: "unusedImport",
+                        data: {
+                            name,
+                        },
+                    });
+                }
             },
         });
     },
diff --git a/src/rules/no-unused-rules.ts b/src/rules/no-unused-rules.ts
index f85a313..fa16e18 100644
--- a/src/rules/no-unused-rules.ts
+++ b/src/rules/no-unused-rules.ts
@@ -12,13 +12,41 @@ const rule: Rule.RuleModule = {
     },
     messages: {
       unused: "Rule '{{ name }}' is never used.",
+      unusedImport: "Library import '{{ name }}' is never used.",
     },
     schema: [],
   },
   create(context: Rule.RuleContext): Rule.RuleListener {
+    const imports = new Map<string,
+      | visitor.AST.ImportBinding
+      | visitor.AST.ImportBindingAll
+      | visitor.AST.ImportBindingDefault
+      | visitor.AST.ImportBindingRename
+    >();
     const rules = new Map<string, visitor.AST.Rule>();
     const refs = new Set<string>();
+    const importRefs = new Set<string>();
     return makeListener({
+      import_binding(node: visitor.AST.ImportBinding): void {
+        if (node.binding.id) {
+          imports.set(node.binding.id.value, node);
+        }
+      },
+      import_binding_all(node: visitor.AST.ImportBindingAll): void {
+        if (node.binding.id) {
+          imports.set(node.binding.id.value, node);
+        }
+      },
+      import_binding_default(node: visitor.AST.ImportBindingDefault): void {
+        if (node.binding.id) {
+          imports.set(node.binding.id.value, node);
+        }
+      },
+      import_binding_rename(node: visitor.AST.ImportBindingRename) {
+        if (node.binding.id) {
+          imports.set(node.binding.id.value, node);
+        }
+      },
       rule(node: visitor.AST.Rule): void {
         if (rules.size === 0) {
           // Default start rule counts as a reference.
@@ -29,9 +57,13 @@ const rule: Rule.RuleModule = {
       rule_ref(node: visitor.AST.RuleReferenceExpression): void {
         refs.add(node.name.value);
       },
+      library_ref(node: visitor.AST.LibraryReferenceExpression): void {
+        importRefs.add(node.library.value);
+      },
       "Program:exit": (): void => {
         for (const name of refs) {
           rules.delete(name);
+          imports.delete(name);
         }
         for (const [name, r] of rules) {
           context.report({
@@ -42,6 +74,18 @@ const rule: Rule.RuleModule = {
             },
           });
         }
+        for (const name of importRefs) {
+          imports.delete(name);
+        }
+        for (const [name, r] of imports) {
+          context.report({
+            node: n(r),
+            messageId: "unusedImport",
+            data: {
+              name,
+            },
+          });
+        }
       },
     });
   },
diff --git a/test/rules/no-unused-rules.test.js b/test/rules/no-unused-rules.test.js
index 75a582c..41a7026 100644
--- a/test/rules/no-unused-rules.test.js
+++ b/test/rules/no-unused-rules.test.js
@@ -15,11 +15,66 @@ foo = bar
 bar = "1"
 `,
     },
+    {
+      code: `
+import * as bar from "bar"
+foo = bar.foo`,
+    },
+    {
+      code: `
+import bar from 'bar'
+foo = bar`,
+    },
+    {
+      code: `
+import {bar} from 'bar'
+foo = bar`,
+    },
+    {
+      code: `
+import {foo as bar} from 'bar'
+foo = bar`,
+    },
+    {
+      code: `
+import {"foo" as bar} from 'bar'
+foo = bar`,
+    },
   ],
   invalid: [
     {
       code: "foo = '1'\nbar = '2'",
       errors: [{ messageId: "unused" }],
     },
+    {
+      code: `
+        import * as bar from "bar"
+        foo = bart.foo`,
+      errors: [{ messageId: "unusedImport" }],
+    },
+    {
+      code: `
+        import bar from "bar"
+        foo = "1"`,
+      errors: [{ messageId: "unusedImport" }],
+    },
+    {
+      code: `
+        import {bar} from "bar"
+        foo = "1"`,
+      errors: [{ messageId: "unusedImport" }],
+    },
+    {
+      code: `
+        import {foo as bar} from "bar"
+        foo = "1"`,
+      errors: [{ messageId: "unusedImport" }],
+    },
+    {
+      code: `
+        import {"foo" as bar} from "bar"
+        foo = "1"`,
+      errors: [{ messageId: "unusedImport" }],
+    },
   ],
 });