diff --git a/src/service/resolve-module-name-literals.ts b/src/service/resolve-module-name-literals.ts
index cc933b0..da179eb 100644
--- a/src/service/resolve-module-name-literals.ts
+++ b/src/service/resolve-module-name-literals.ts
@@ -1,8 +1,8 @@
 import ts from 'typescript'
 import { equivalents } from '../equivalents.js'
+import { getCurrentDirectory } from '../ts-sys-cached.js'
 import { addRootFile } from './file-versions.js'
 import { getCanonicalFileName } from './get-canonical-filename.js'
-import { getCurrentDirectory } from '../ts-sys-cached.js'
 import { tsconfig } from './tsconfig.js'
 
 // reset cache on config change
@@ -46,10 +46,12 @@ const fixupResolvedModule = (
     | ts.ResolvedTypeReferenceDirective
 ) => {
   const { resolvedFileName } = resolvedModule
+  /* c8 ignore next */
   if (resolvedFileName === undefined) return
   // [MUST_UPDATE_FOR_NEW_FILE_EXTENSIONS]
   // .ts,.mts,.cts is always switched to internal
   // .js is switched on-demand
+  /* c8 ignore start */
   if (
     resolvedModule.isExternalLibraryImport &&
     ((resolvedFileName.endsWith('.ts') &&
@@ -63,6 +65,7 @@ const fixupResolvedModule = (
   ) {
     resolvedModule.isExternalLibraryImport = false
   }
+  /* c8 ignore stop */
   if (!resolvedModule.isExternalLibraryImport) {
     knownInternalFilenames.add(resolvedFileName)
   }
@@ -89,7 +92,6 @@ export const getResolveModuleNameLiterals = (
     containingSourceFile,
     _reusedNames
   ) => {
-    // moduleLiterals[n].text is the equivalent to moduleName string
     return moduleLiterals.map((moduleLiteral, i) => {
       const moduleName = moduleLiteral.text
       const mode = containingSourceFile
@@ -104,7 +106,9 @@ export const getResolveModuleNameLiterals = (
                 | undefined
             }
           ).getModeForResolutionAtIndex?.(containingSourceFile, i)
-        : undefined
+        : /* c8 ignore start */
+          undefined
+      /* c8 ignore stop */
       let { resolvedModule } = ts.resolveModuleName(
         moduleName,
         containingFile,
@@ -119,7 +123,10 @@ export const getResolveModuleNameLiterals = (
         const ext =
           lastDotIndex >= 0 ? moduleName.slice(lastDotIndex) : ''
         if (ext) {
-          const replacements = equivalents(moduleName)
+          const replacements = equivalents(
+            moduleName,
+            mode !== ts.ModuleKind.ESNext
+          )
           for (const rep of replacements) {
             ;({ resolvedModule } = ts.resolveModuleName(
               rep,
diff --git a/src/service/resolve-type-reference-directive-references.ts b/src/service/resolve-type-reference-directive-references.ts
index d864efc..f379e1a 100644
--- a/src/service/resolve-type-reference-directive-references.ts
+++ b/src/service/resolve-type-reference-directive-references.ts
@@ -4,9 +4,8 @@ import { getCanonicalFileName } from './get-canonical-filename.js'
 import { getCurrentDirectory } from '../ts-sys-cached.js'
 import { tsconfig } from './tsconfig.js'
 
-const config = tsconfig()
-
-const resolveTypeReferenceDirectiveReferencesInternalCache = new Map<
+// ResolveTypeReferenceDirectiveReferences internal cache
+const rtrdrInternalCache = new Map<
   string,
   ts.ResolvedTypeReferenceDirectiveWithFailedLookupLocations
 >()
@@ -15,6 +14,7 @@ export const getResolveTypeReferenceDirectiveReferences = (
   host: ts.LanguageServiceHost,
   moduleResolutionCache: ts.ModuleResolutionCache
 ) => {
+  const config = tsconfig()
   const typeReferenceDirectiveResolutionCache =
     ts.createTypeReferenceDirectiveResolutionCache(
       getCurrentDirectory(),
@@ -22,12 +22,14 @@ export const getResolveTypeReferenceDirectiveReferences = (
       config.options,
       moduleResolutionCache.getPackageJsonInfoCache()
     )
+
   const resolveTypeReferenceDirectiveReferences = (
     typeDirectiveReferences: readonly (ts.FileReference | string)[],
     containingFile: string,
     redirectedReference: ts.ResolvedProjectReference | undefined,
     options: ts.CompilerOptions,
-    containingSourceFile: ts.SourceFile | string | undefined
+    containingSourceFile: ts.SourceFile | string | undefined,
+    _reusedNames?: (ts.FileReference | string)[]
   ): readonly ts.ResolvedTypeReferenceDirectiveWithFailedLookupLocations[] => {
     const entries = typeDirectiveReferences
     const resolutionCache = typeReferenceDirectiveResolutionCache
@@ -40,11 +42,11 @@ export const getResolveTypeReferenceDirectiveReferences = (
       resolutionCache: ts.TypeReferenceDirectiveResolutionCache
     ) => any
 
+    /* c8 ignore start */
     if (typeDirectiveReferences.length === 0) return []
+    /* c8 ignore stop */
     const resolutions: any[] = []
 
-    const cache = resolveTypeReferenceDirectiveReferencesInternalCache
-
     const loader = createLoader(
       containingFile,
       redirectedReference,
@@ -59,13 +61,14 @@ export const getResolveTypeReferenceDirectiveReferences = (
         containingSourceFile
       )
       const key = createModeAwareCacheKey(name, mode)
-      let result = cache.get(key)
+      let result = rtrdrInternalCache.get(key)
       if (!result) {
-        cache.set(key, (result = loader.resolve(name, mode)))
+        rtrdrInternalCache.set(key, (result = loader.resolve(name, mode)))
       }
       resolutions.push(result)
     }
     return resolutions
   }
+
   return resolveTypeReferenceDirectiveReferences
 }
diff --git a/test/service/resolve-module-name-literals.ts b/test/service/resolve-module-name-literals.ts
index e69de29..a3bd08c 100644
--- a/test/service/resolve-module-name-literals.ts
+++ b/test/service/resolve-module-name-literals.ts
@@ -0,0 +1,107 @@
+import { resolve } from 'path'
+import t from 'tap'
+// import { fileURLToPath } from 'url'
+// import { getLanguageService } from '../../src/service/language-service.js'
+// import { markFileNameInternal } from '../../src/service/resolve-module-name-literals.js'
+//
+// const svc = getLanguageService()
+// svc.getProgram()
+//
+// markFileNameInternal(fileURLToPath(import.meta.url))
+
+t.test('commonjs program', async t => {
+  const dir = t.testdir({
+    'tsconfig.json': JSON.stringify({
+      include: ['index.ts'],
+      compilerOptions: {
+        esModuleInterop: true,
+        forceConsistentCasingInFileNames: true,
+        module: 'commonjs',
+        moduleResolution: 'node10',
+        skipLibCheck: true,
+        strict: true,
+        target: 'es2022',
+      },
+    }),
+    'package.json': JSON.stringify({ type: 'commonjs' }),
+    'index.ts': `
+import assert from 'node:assert'
+import './def'
+import { bar } from './bar'
+import { baz } from './baz'
+import t from 'tap'
+assert.equal(1, 1)
+export type Foo = {
+  foo: string
+}
+export const foo = (f: Foo) => f.foo
+`,
+    'bar.cts': `
+export const bar = 'bar'
+`,
+    'baz.ts': `
+export const baz = 'baz'
+`,
+  })
+  const cwd = process.cwd()
+  process.chdir(dir)
+  t.teardown(() => process.chdir(cwd))
+  const { getLanguageService } = (await t.mockImport(
+    '../../src/service/language-service.js'
+  )) as typeof import('../../src/service/language-service.js')
+  const { markFileNameInternal } = (await t.mockImport(
+    '../../src/service/resolve-module-name-literals.js'
+  )) as typeof import('../../src/service/resolve-module-name-literals.js')
+  const svc = getLanguageService()
+  svc.getHost().resolveModuleNameLiterals
+  svc.getProgram()
+  markFileNameInternal(resolve(dir, 'index.ts'))
+})
+
+t.test('esm program', async t => {
+  const dir = t.testdir({
+    'tsconfig.json': JSON.stringify({
+      include: ['index.ts'],
+      compilerOptions: {
+        esModuleInterop: true,
+        forceConsistentCasingInFileNames: true,
+        module: 'nodenext',
+        moduleResolution: 'nodenext',
+        skipLibCheck: true,
+        strict: true,
+        target: 'es2022',
+      },
+    }),
+    'package.json': JSON.stringify({ type: 'module' }),
+    'index.ts': `
+import assert from 'node:assert'
+import { bar } from './bar.cjs'
+import { baz } from './baz.js'
+import t from 'tap'
+assert.equal(1, 1)
+export type Foo = {
+  foo: string
+}
+export const foo = (f: Foo) => f.foo
+`,
+    'bar.cts': `
+export const bar = 'bar'
+`,
+    'baz.ts': `
+export const baz = 'baz'
+`,
+  })
+  const cwd = process.cwd()
+  process.chdir(dir)
+  t.teardown(() => process.chdir(cwd))
+  const { getLanguageService } = (await t.mockImport(
+    '../../src/service/language-service.js'
+  )) as typeof import('../../src/service/language-service.js')
+  const { markFileNameInternal } = (await t.mockImport(
+    '../../src/service/resolve-module-name-literals.js'
+  )) as typeof import('../../src/service/resolve-module-name-literals.js')
+  const svc = getLanguageService()
+  svc.getHost().resolveModuleNameLiterals
+  svc.getProgram()
+  markFileNameInternal(resolve(dir, 'index.ts'))
+})
diff --git a/test/service/resolve-type-reference-directive-references.ts b/test/service/resolve-type-reference-directive-references.ts
index e69de29..b0ca19a 100644
--- a/test/service/resolve-type-reference-directive-references.ts
+++ b/test/service/resolve-type-reference-directive-references.ts
@@ -0,0 +1,5 @@
+import t from 'tap'
+import { getLanguageService } from '../../src/service/language-service.js'
+
+getLanguageService().getProgram()
+t.pass('just a test file for coverage purposes, nothing to do')
diff --git a/tsconfig.json b/tsconfig.json
index d8a5105..7f39495 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -1,10 +1,4 @@
 {
-  // settings for tsimp importer
-  "tsimp": {
-    "compilerOptions": {
-      "resolveJsonModule": false
-    }
-  },
   "compilerOptions": {
     "declaration": true,
     "declarationMap": true,