Disallow import assertions in nodenext

Author: andrewbranch

src/compiler/checker.ts

@@ -48076,6 +48076,10 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
                 );
             }
 
+            if (moduleKind === ModuleKind.NodeNext && !isImportAttributes) {
+                return grammarErrorOnFirstToken(node, Diagnostics.Import_assertions_have_been_replaced_by_import_attributes_Use_with_instead_of_asserts);
+            }
+
             if (declaration.moduleSpecifier && getEmitSyntaxForModuleSpecifierExpression(declaration.moduleSpecifier) === ModuleKind.CommonJS) {
                 return grammarErrorOnNode(
                     node,

src/compiler/diagnosticMessages.json

@@ -3980,6 +3980,10 @@
         "category": "Error",
         "code": 2879
     },
+    "Import assertions have been replaced by import attributes. Use 'with' instead of 'asserts'.": {
+        "category": "Error",
+        "code": 2880
+    },
 
     "Import declaration '{0}' is using private name '{1}'.": {
         "category": "Error",

tests/baselines/reference/importAssertionNonstring.errors.txt

@@ -1,25 +1,33 @@
+mod.mts(1,37): error TS2880: Import assertions have been replaced by import attributes. Use 'with' instead of 'asserts'.
 mod.mts(1,37): error TS2322: Type '{ field: 0; }' is not assignable to type 'ImportAttributes'.
   Property 'field' is incompatible with index signature.
     Type 'number' is not assignable to type 'string'.
 mod.mts(1,52): error TS2837: Import assertion values must be string literal expressions.
+mod.mts(3,37): error TS2880: Import assertions have been replaced by import attributes. Use 'with' instead of 'asserts'.
 mod.mts(3,52): error TS2837: Import assertion values must be string literal expressions.
+mod.mts(5,37): error TS2880: Import assertions have been replaced by import attributes. Use 'with' instead of 'asserts'.
 mod.mts(5,37): error TS2322: Type '{ field: RegExp; }' is not assignable to type 'ImportAttributes'.
   Property 'field' is incompatible with index signature.
     Type 'RegExp' is not assignable to type 'string'.
 mod.mts(5,52): error TS2837: Import assertion values must be string literal expressions.
+mod.mts(7,37): error TS2880: Import assertions have been replaced by import attributes. Use 'with' instead of 'asserts'.
 mod.mts(7,37): error TS2322: Type '{ field: string[]; }' is not assignable to type 'ImportAttributes'.
   Property 'field' is incompatible with index signature.
     Type 'string[]' is not assignable to type 'string'.
 mod.mts(7,52): error TS2837: Import assertion values must be string literal expressions.
+mod.mts(9,37): error TS2880: Import assertions have been replaced by import attributes. Use 'with' instead of 'asserts'.
 mod.mts(9,37): error TS2322: Type '{ field: { a: number; }; }' is not assignable to type 'ImportAttributes'.
   Property 'field' is incompatible with index signature.
     Type '{ a: number; }' is not assignable to type 'string'.
 mod.mts(9,52): error TS2837: Import assertion values must be string literal expressions.
+mod.mts(11,37): error TS2880: Import assertions have been replaced by import attributes. Use 'with' instead of 'asserts'.
 mod.mts(11,66): error TS2837: Import assertion values must be string literal expressions.
 
 
-==== mod.mts (10 errors) ====
+==== mod.mts (16 errors) ====
     import * as thing1 from "./mod.mjs" assert {field: 0};
+                                        ~~~~~~
+!!! error TS2880: Import assertions have been replaced by import attributes. Use 'with' instead of 'asserts'.
                                         ~~~~~~~~~~~~~~~~~
 !!! error TS2322: Type '{ field: 0; }' is not assignable to type 'ImportAttributes'.
 !!! error TS2322:   Property 'field' is incompatible with index signature.
@@ -28,10 +36,14 @@ mod.mts(11,66): error TS2837: Import assertion values must be string literal exp
 !!! error TS2837: Import assertion values must be string literal expressions.
 
     import * as thing2 from "./mod.mjs" assert {field: `a`};
+                                        ~~~~~~
+!!! error TS2880: Import assertions have been replaced by import attributes. Use 'with' instead of 'asserts'.
                                                        ~~~
 !!! error TS2837: Import assertion values must be string literal expressions.
 
     import * as thing3 from "./mod.mjs" assert {field: /a/g};
+                                        ~~~~~~
+!!! error TS2880: Import assertions have been replaced by import attributes. Use 'with' instead of 'asserts'.
                                         ~~~~~~~~~~~~~~~~~~~~
 !!! error TS2322: Type '{ field: RegExp; }' is not assignable to type 'ImportAttributes'.
 !!! error TS2322:   Property 'field' is incompatible with index signature.
@@ -40,6 +52,8 @@ mod.mts(11,66): error TS2837: Import assertion values must be string literal exp
 !!! error TS2837: Import assertion values must be string literal expressions.
 
     import * as thing4 from "./mod.mjs" assert {field: ["a"]};
+                                        ~~~~~~
+!!! error TS2880: Import assertions have been replaced by import attributes. Use 'with' instead of 'asserts'.
                                         ~~~~~~~~~~~~~~~~~~~~~
 !!! error TS2322: Type '{ field: string[]; }' is not assignable to type 'ImportAttributes'.
 !!! error TS2322:   Property 'field' is incompatible with index signature.
@@ -48,6 +62,8 @@ mod.mts(11,66): error TS2837: Import assertion values must be string literal exp
 !!! error TS2837: Import assertion values must be string literal expressions.
 
     import * as thing5 from "./mod.mjs" assert {field: { a: 0 }};
+                                        ~~~~~~
+!!! error TS2880: Import assertions have been replaced by import attributes. Use 'with' instead of 'asserts'.
                                         ~~~~~~~~~~~~~~~~~~~~~~~~
 !!! error TS2322: Type '{ field: { a: number; }; }' is not assignable to type 'ImportAttributes'.
 !!! error TS2322:   Property 'field' is incompatible with index signature.
@@ -56,5 +72,7 @@ mod.mts(11,66): error TS2837: Import assertion values must be string literal exp
 !!! error TS2837: Import assertion values must be string literal expressions.
 
     import * as thing6 from "./mod.mjs" assert {type: "json", field: 0..toString()}
+                                        ~~~~~~
+!!! error TS2880: Import assertions have been replaced by import attributes. Use 'with' instead of 'asserts'.
                                                                      ~~~~~~~~~~~~~
 !!! error TS2837: Import assertion values must be string literal expressions.

tests/baselines/reference/nodeModulesImportAssertions(module=nodenext).errors.txt

@@ -1,12 +1,15 @@
-otherc.cts(1,35): error TS2836: Import assertions are not allowed on statements that compile to CommonJS 'require' calls.
+index.ts(1,35): error TS2880: Import assertions have been replaced by import attributes. Use 'with' instead of 'asserts'.
+otherc.cts(1,35): error TS2880: Import assertions have been replaced by import attributes. Use 'with' instead of 'asserts'.
 
 
-==== index.ts (0 errors) ====
+==== index.ts (1 errors) ====
     import json from "./package.json" assert { type: "json" };
+                                      ~~~~~~
+!!! error TS2880: Import assertions have been replaced by import attributes. Use 'with' instead of 'asserts'.
 ==== otherc.cts (1 errors) ====
     import json from "./package.json" assert { type: "json" }; // should error, cjs mode imports don't support assertions
-                                      ~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2836: Import assertions are not allowed on statements that compile to CommonJS 'require' calls.
+                                      ~~~~~~
+!!! error TS2880: Import assertions have been replaced by import attributes. Use 'with' instead of 'asserts'.
     const json2 = import("./package.json", { assert: { type: "json" } }); // should be fine
 ==== package.json (0 errors) ====
     {

tests/baselines/reference/nodeModulesImportModeDeclarationEmit1(module=nodenext).errors.txt

@@ -1,6 +1,6 @@
-/index.ts(6,50): error TS2836: Import assertions are not allowed on statements that compile to CommonJS 'require' calls.
+/index.ts(6,50): error TS2880: Import assertions have been replaced by import attributes. Use 'with' instead of 'asserts'.
 /index.ts(7,14): error TS2305: Module '"pkg"' has no exported member 'ImportInterface'.
-/index.ts(7,49): error TS2836: Import assertions are not allowed on statements that compile to CommonJS 'require' calls.
+/index.ts(7,49): error TS2880: Import assertions have been replaced by import attributes. Use 'with' instead of 'asserts'.
 
 
 ==== /index.ts (3 errors) ====
@@ -10,13 +10,13 @@
     export interface LocalInterface extends RequireInterface, ImportInterface {}
 
     import {type RequireInterface as Req} from "pkg" assert { "resolution-mode": "require" };
-                                                     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2836: Import assertions are not allowed on statements that compile to CommonJS 'require' calls.
+                                                     ~~~~~~
+!!! error TS2880: Import assertions have been replaced by import attributes. Use 'with' instead of 'asserts'.
     import {type ImportInterface as Imp} from "pkg" assert { "resolution-mode": "import" };
                  ~~~~~~~~~~~~~~~
 !!! error TS2305: Module '"pkg"' has no exported member 'ImportInterface'.
-                                                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2836: Import assertions are not allowed on statements that compile to CommonJS 'require' calls.
+                                                    ~~~~~~
+!!! error TS2880: Import assertions have been replaced by import attributes. Use 'with' instead of 'asserts'.
     export interface Loc extends Req, Imp {}
 
     export type { RequireInterface } from "pkg" assert { "resolution-mode": "require" };

tests/baselines/reference/nodeModulesImportModeDeclarationEmit2(module=nodenext).errors.txt

@@ -1,6 +1,6 @@
 /index.ts(6,14): error TS2305: Module '"pkg"' has no exported member 'RequireInterface'.
-/index.ts(6,50): error TS1454: `resolution-mode` can only be set for type-only imports.
-/index.ts(7,49): error TS1454: `resolution-mode` can only be set for type-only imports.
+/index.ts(6,50): error TS2880: Import assertions have been replaced by import attributes. Use 'with' instead of 'asserts'.
+/index.ts(7,49): error TS2880: Import assertions have been replaced by import attributes. Use 'with' instead of 'asserts'.
 
 
 ==== /index.ts (3 errors) ====
@@ -12,11 +12,11 @@
     import {type RequireInterface as Req} from "pkg" assert { "resolution-mode": "require" };
                  ~~~~~~~~~~~~~~~~
 !!! error TS2305: Module '"pkg"' has no exported member 'RequireInterface'.
-                                                     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS1454: `resolution-mode` can only be set for type-only imports.
+                                                     ~~~~~~
+!!! error TS2880: Import assertions have been replaced by import attributes. Use 'with' instead of 'asserts'.
     import {type ImportInterface as Imp} from "pkg" assert { "resolution-mode": "import" };
-                                                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS1454: `resolution-mode` can only be set for type-only imports.
+                                                    ~~~~~~
+!!! error TS2880: Import assertions have been replaced by import attributes. Use 'with' instead of 'asserts'.
     export interface Loc extends Req, Imp {}
 
     export type { RequireInterface } from "pkg" assert { "resolution-mode": "require" };

tests/baselines/reference/nodeModulesImportModeDeclarationEmitErrors1(module=nodenext).errors.txt

@@ -1,27 +1,27 @@
-/index.ts(2,45): error TS2836: Import assertions are not allowed on statements that compile to CommonJS 'require' calls.
+/index.ts(2,45): error TS2880: Import assertions have been replaced by import attributes. Use 'with' instead of 'asserts'.
 /index.ts(2,73): error TS1453: `resolution-mode` should be either `require` or `import`.
 /index.ts(4,10): error TS2305: Module '"pkg"' has no exported member 'ImportInterface'.
-/index.ts(4,39): error TS2836: Import assertions are not allowed on statements that compile to CommonJS 'require' calls.
-/index.ts(6,76): error TS2836: Import assertions are not allowed on statements that compile to CommonJS 'require' calls.
+/index.ts(4,39): error TS2880: Import assertions have been replaced by import attributes. Use 'with' instead of 'asserts'.
+/index.ts(6,76): error TS2880: Import assertions have been replaced by import attributes. Use 'with' instead of 'asserts'.
 
 
 ==== /index.ts (5 errors) ====
     // incorrect mode
     import type { RequireInterface } from "pkg" assert { "resolution-mode": "foobar" };
-                                                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2836: Import assertions are not allowed on statements that compile to CommonJS 'require' calls.
+                                                ~~~~~~
+!!! error TS2880: Import assertions have been replaced by import attributes. Use 'with' instead of 'asserts'.
                                                                             ~~~~~~~~
 !!! error TS1453: `resolution-mode` should be either `require` or `import`.
     // not type-only
     import { ImportInterface } from "pkg" assert { "resolution-mode": "import" };
              ~~~~~~~~~~~~~~~
 !!! error TS2305: Module '"pkg"' has no exported member 'ImportInterface'.
-                                          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2836: Import assertions are not allowed on statements that compile to CommonJS 'require' calls.
+                                          ~~~~~~
+!!! error TS2880: Import assertions have been replaced by import attributes. Use 'with' instead of 'asserts'.
     // not exclusively type-only
     import {type RequireInterface as Req, RequireInterface as Req2} from "pkg" assert { "resolution-mode": "require" };
-                                                                               ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2836: Import assertions are not allowed on statements that compile to CommonJS 'require' calls.
+                                                                               ~~~~~~
+!!! error TS2880: Import assertions have been replaced by import attributes. Use 'with' instead of 'asserts'.
 
     export interface LocalInterface extends RequireInterface, ImportInterface {}