typescript-eslint · JoshuaKGoldberg · Mar 5, 2024 · Dec 3, 2023 · Feb 3, 2024 · Feb 3, 2024
diff --git a/eslint.config.mjs b/eslint.config.mjs
@@ -132,7 +132,6 @@ export default tseslint.config(
         { allowIIFEs: true },
       ],
       '@typescript-eslint/no-explicit-any': 'error',
-      '@typescript-eslint/no-non-null-assertion': 'off',
       'no-constant-condition': 'off',
       '@typescript-eslint/no-unnecessary-condition': [
         'error',
@@ -343,6 +342,7 @@ export default tseslint.config(
         'error',
         { allow: ['arrowFunctions'] },
       ],
+      '@typescript-eslint/no-non-null-assertion': 'off',
       '@typescript-eslint/no-unsafe-assignment': 'off',
       '@typescript-eslint/no-unsafe-call': 'off',
       '@typescript-eslint/no-unsafe-member-access': 'off',

diff --git a/packages/eslint-plugin-internal/src/rules/plugin-test-formatting.ts b/packages/eslint-plugin-internal/src/rules/plugin-test-formatting.ts
@@ -55,6 +55,7 @@ function getExpectedIndentForNode(
   sourceCodeLines: string[],
 ): number {
   const lineIdx = node.loc.start.line - 1;
+  // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
   const indent = START_OF_LINE_WHITESPACE_MATCHER.exec(
     sourceCodeLines[lineIdx],
   )![1];
@@ -348,6 +349,7 @@ export default createRule<Options, MessageIds>({
       // +2 because we expect the string contents are indented one level
       const expectedIndent = parentIndent + 2;
 
+      // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
       const firstLineIndent = START_OF_LINE_WHITESPACE_MATCHER.exec(
         lines[0],
       )![1];
@@ -370,6 +372,7 @@ export default createRule<Options, MessageIds>({
             continue;
           }
 
+          // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
           const matches = START_OF_LINE_WHITESPACE_MATCHER.exec(line)!;
 
           const indent = matches[1];

diff --git a/packages/eslint-plugin/src/rules/ban-ts-comment.ts b/packages/eslint-plugin/src/rules/ban-ts-comment.ts
@@ -131,6 +131,7 @@ export default createRule<[Options], MessageIds>({
           if (!match) {
             return;
           }
+          // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
           const { directive, description } = match.groups!;
 
           const fullDirective = `ts-${directive}` as keyof Options;

diff --git a/packages/eslint-plugin/src/rules/block-spacing.ts b/packages/eslint-plugin/src/rules/block-spacing.ts
@@ -1,3 +1,4 @@
+/* eslint-disable @typescript-eslint/no-non-null-assertion */
 import type { TSESTree } from '@typescript-eslint/utils';
 import { AST_TOKEN_TYPES } from '@typescript-eslint/utils';
 

diff --git a/packages/eslint-plugin/src/rules/brace-style.ts b/packages/eslint-plugin/src/rules/brace-style.ts
@@ -1,3 +1,4 @@
+/* eslint-disable @typescript-eslint/no-non-null-assertion */
 import type { TSESTree } from '@typescript-eslint/utils';
 
 import type {

diff --git a/packages/eslint-plugin/src/rules/comma-spacing.ts b/packages/eslint-plugin/src/rules/comma-spacing.ts
@@ -71,6 +71,7 @@ export default createRule<Options, MessageIds>({
       for (const element of node.elements) {
         let token: TSESTree.Token | null;
         if (element == null) {
+          // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
           token = context.sourceCode.getTokenAfter(previousToken!);
           if (token && isCommaToken(token)) {
             ignoredTokens.add(token);

diff --git a/packages/eslint-plugin/src/rules/consistent-generic-constructors.ts b/packages/eslint-plugin/src/rules/consistent-generic-constructors.ts
@@ -1,7 +1,7 @@
 import type { TSESTree } from '@typescript-eslint/utils';
 import { AST_NODE_TYPES } from '@typescript-eslint/utils';
 
-import { createRule } from '../util';
+import { createRule, nullThrows, NullThrowsReasons } from '../util';
 
 type MessageIds = 'preferConstructor' | 'preferTypeAnnotation';
 type Options = ['constructor' | 'type-annotation'];
@@ -94,7 +94,10 @@ export default createRule<Options, MessageIds>({
                   }
                   // If the property's computed, we have to attach the
                   // annotation after the square bracket, not the enclosed expression
-                  return context.sourceCode.getTokenAfter(node.key)!;
+                  return nullThrows(
+                    context.sourceCode.getTokenAfter(node.key),
+                    NullThrowsReasons.MissingToken(']', 'key'),
+                  );
                 }
                 return [
                   fixer.remove(typeArguments),

diff --git a/packages/eslint-plugin/src/rules/consistent-type-assertions.ts b/packages/eslint-plugin/src/rules/consistent-type-assertions.ts
@@ -9,6 +9,8 @@ import {
   isClosingParenToken,
   isOpeningParenToken,
   isParenthesized,
+  nullThrows,
+  NullThrowsReasons,
 } from '../util';
 import { getWrappedCode } from '../util/getWrappedCode';
 
@@ -109,14 +111,14 @@ export default createRule<Options, MessageIds>({
       let afterCount = 0;
 
       if (isParenthesized(node, context.sourceCode)) {
-        const bodyOpeningParen = context.sourceCode.getTokenBefore(
-          node,
-          isOpeningParenToken,
-        )!;
-        const bodyClosingParen = context.sourceCode.getTokenAfter(
-          node,
-          isClosingParenToken,
-        )!;
+        const bodyOpeningParen = nullThrows(
+          context.sourceCode.getTokenBefore(node, isOpeningParenToken),
+          NullThrowsReasons.MissingToken('(', 'node'),
+        );
+        const bodyClosingParen = nullThrows(
+          context.sourceCode.getTokenAfter(node, isClosingParenToken),
+          NullThrowsReasons.MissingToken(')', 'node'),
+        );
 
         beforeCount = node.range[0] - bodyOpeningParen.range[0];
         afterCount = bodyClosingParen.range[1] - node.range[1];

diff --git a/packages/eslint-plugin/src/rules/consistent-type-imports.ts b/packages/eslint-plugin/src/rules/consistent-type-imports.ts
@@ -529,7 +529,10 @@ export default createRule<Options, MessageIds>({
       const last = namedSpecifierGroup[namedSpecifierGroup.length - 1];
       const removeRange: TSESTree.Range = [first.range[0], last.range[1]];
       const textRange: TSESTree.Range = [...removeRange];
-      const before = context.sourceCode.getTokenBefore(first)!;
+      const before = nullThrows(
+        context.sourceCode.getTokenBefore(first),
+        NullThrowsReasons.MissingToken('token', 'first specifier'),
+      );
       textRange[0] = before.range[1];
       if (isCommaToken(before)) {
         removeRange[0] = before.range[0];
@@ -539,7 +542,10 @@ export default createRule<Options, MessageIds>({
 
       const isFirst = allNamedSpecifiers[0] === first;
       const isLast = allNamedSpecifiers[allNamedSpecifiers.length - 1] === last;
-      const after = context.sourceCode.getTokenAfter(last)!;
+      const after = nullThrows(
+        context.sourceCode.getTokenAfter(last),
+        NullThrowsReasons.MissingToken('token', 'last specifier'),
+      );
       textRange[1] = after.range[0];
       if (isFirst || isLast) {
         if (isCommaToken(after)) {
@@ -566,13 +572,20 @@ export default createRule<Options, MessageIds>({
     ): TSESLint.RuleFix {
       const closingBraceToken = nullThrows(
         context.sourceCode.getFirstTokenBetween(
-          context.sourceCode.getFirstToken(target)!,
+          nullThrows(
+            context.sourceCode.getFirstToken(target),
+            NullThrowsReasons.MissingToken('token before', 'import'),
+          ),
           target.source,
           isClosingBraceToken,
         ),
         NullThrowsReasons.MissingToken('}', target.type),
       );
-      const before = context.sourceCode.getTokenBefore(closingBraceToken)!;
+      const before = nullThrows(
+        context.sourceCode.getTokenBefore(closingBraceToken),
+        NullThrowsReasons.MissingToken('token before', 'closing brace'),
+      );
+
       if (!isCommaToken(before) && !isOpeningBraceToken(before)) {
         insertText = `,${insertText}`;
       }

diff --git a/packages/eslint-plugin/src/rules/enum-utils/shared.ts b/packages/eslint-plugin/src/rules/enum-utils/shared.ts
@@ -12,12 +12,15 @@ import { isTypeFlagSet } from '../../util';
  * - `Fruit.Apple` --> `Fruit`
  */
 function getBaseEnumType(typeChecker: ts.TypeChecker, type: ts.Type): ts.Type {
+  // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
   const symbol = type.getSymbol()!;
   if (!tsutils.isSymbolFlagSet(symbol, ts.SymbolFlags.EnumMember)) {
     return type;
   }
 
-  return typeChecker.getTypeAtLocation(symbol.valueDeclaration!.parent);
+  return typeChecker.getTypeAtLocation(
+    (symbol.valueDeclaration as ts.EnumMember).parent,
+  );
 }
 
 /**

diff --git a/packages/eslint-plugin/src/rules/explicit-member-accessibility.ts b/packages/eslint-plugin/src/rules/explicit-member-accessibility.ts
@@ -1,7 +1,12 @@
 import type { TSESLint, TSESTree } from '@typescript-eslint/utils';
 import { AST_NODE_TYPES, AST_TOKEN_TYPES } from '@typescript-eslint/utils';
 
-import { createRule, getNameFromMember } from '../util';
+import {
+  createRule,
+  getNameFromMember,
+  nullThrows,
+  NullThrowsReasons,
+} from '../util';
 
 type AccessibilityLevel =
   | 'explicit' // require an accessor (including public)
@@ -182,7 +187,7 @@ export default createRule<Options, MessageIds>({
     ): TSESLint.ReportFixFunction {
       return function (fixer: TSESLint.RuleFixer): TSESLint.RuleFix {
         const tokens = context.sourceCode.getTokens(node);
-        let rangeToRemove: TSESLint.AST.Range;
+        let rangeToRemove!: TSESLint.AST.Range;
         for (let i = 0; i < tokens.length; i++) {
           const token = tokens[i];
           if (
@@ -207,7 +212,7 @@ export default createRule<Options, MessageIds>({
             }
           }
         }
-        return fixer.removeRange(rangeToRemove!);
+        return fixer.removeRange(rangeToRemove);
       };
     }
 
@@ -228,7 +233,10 @@ export default createRule<Options, MessageIds>({
       ): TSESLint.RuleFix | null {
         if (node.decorators.length) {
           const lastDecorator = node.decorators[node.decorators.length - 1];
-          const nextToken = context.sourceCode.getTokenAfter(lastDecorator)!;
+          const nextToken = nullThrows(
+            context.sourceCode.getTokenAfter(lastDecorator),
+            NullThrowsReasons.MissingToken('token', 'last decorator'),
+          );
           return fixer.insertTextBefore(nextToken, `${accessibility} `);
         }
         return fixer.insertTextBefore(node, `${accessibility} `);

diff --git a/packages/eslint-plugin/src/rules/func-call-spacing.ts b/packages/eslint-plugin/src/rules/func-call-spacing.ts
@@ -1,3 +1,4 @@
+/* eslint-disable @typescript-eslint/no-non-null-assertion */
 import type { TSESTree } from '@typescript-eslint/utils';
 
 import {

diff --git a/packages/eslint-plugin/src/rules/indent.ts b/packages/eslint-plugin/src/rules/indent.ts
@@ -380,6 +380,7 @@ export default createRule<Options, MessageIds>({
       },
 
       TSMappedType(node: TSESTree.TSMappedType) {
+        // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
         const squareBracketStart = context.sourceCode.getTokenBefore(
           node.typeParameter,
         )!;

diff --git a/packages/eslint-plugin/src/rules/key-spacing.ts b/packages/eslint-plugin/src/rules/key-spacing.ts
@@ -1,3 +1,4 @@
+/* eslint-disable @typescript-eslint/no-non-null-assertion */
 import type { TSESTree } from '@typescript-eslint/utils';
 import { AST_NODE_TYPES } from '@typescript-eslint/utils';
 

diff --git a/packages/eslint-plugin/src/rules/keyword-spacing.ts b/packages/eslint-plugin/src/rules/keyword-spacing.ts
@@ -1,3 +1,4 @@
+/* eslint-disable @typescript-eslint/no-non-null-assertion */
 import type { TSESTree } from '@typescript-eslint/utils';
 import { AST_NODE_TYPES, AST_TOKEN_TYPES } from '@typescript-eslint/utils';
 import type { JSONSchema4 } from '@typescript-eslint/utils/json-schema';

diff --git a/packages/eslint-plugin/src/rules/lines-around-comment.ts b/packages/eslint-plugin/src/rules/lines-around-comment.ts
@@ -1,3 +1,4 @@
+/* eslint-disable @typescript-eslint/no-non-null-assertion */
 import type { TSESTree } from '@typescript-eslint/utils';
 import { AST_NODE_TYPES, AST_TOKEN_TYPES } from '@typescript-eslint/utils';
 

diff --git a/packages/eslint-plugin/src/rules/member-ordering.ts b/packages/eslint-plugin/src/rules/member-ordering.ts
@@ -506,6 +506,7 @@ function getRankOrder(
   const stack = memberGroups.slice(); // Get a copy of the member groups
 
   while (stack.length > 0 && rank === -1) {
+    // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
     const memberGroup = stack.shift()!;
     rank = orderConfig.findIndex(memberType =>
       Array.isArray(memberType)
@@ -993,6 +994,8 @@ export default createRule<Options, MessageIds>({
       }
     }
 
+    // https://github.com/typescript-eslint/typescript-eslint/issues/5439
+    /* eslint-disable @typescript-eslint/no-non-null-assertion */
     return {
       ClassDeclaration(node): void {
         validateMembersOrder(
@@ -1023,5 +1026,6 @@ export default createRule<Options, MessageIds>({
         );
       },
     };
+    /* eslint-enable @typescript-eslint/no-non-null-assertion */
   },
 });