diff --git a/packages/compiler-cli/src/ngtsc/annotations/src/util.ts b/packages/compiler-cli/src/ngtsc/annotations/src/util.ts
index 4d52eb6b80..073fa02897 100644
--- a/packages/compiler-cli/src/ngtsc/annotations/src/util.ts
+++ b/packages/compiler-cli/src/ngtsc/annotations/src/util.ts
@@ -516,7 +516,13 @@ export function resolveProvidersRequiringFactory(
       }
     }
 
-    if (tokenClass !== null && reflector.isClass(tokenClass.node)) {
+    // TODO(alxhub): there was a bug where `getConstructorParameters` would return `null` for a
+    // class in a .d.ts file, always, even if the class had a constructor. This was fixed for
+    // `getConstructorParameters`, but that fix causes more classes to be recognized here as needing
+    // provider checks, which is a breaking change in g3. Avoid this breakage for now by skipping
+    // classes from .d.ts files here directly, until g3 can be cleaned up.
+    if (tokenClass !== null && !tokenClass.node.getSourceFile().isDeclarationFile &&
+        reflector.isClass(tokenClass.node)) {
       const constructorParameters = reflector.getConstructorParameters(tokenClass.node);
 
       // Note that we only want to capture providers with a non-trivial constructor,
diff --git a/packages/compiler-cli/test/ngtsc/ngtsc_spec.ts b/packages/compiler-cli/test/ngtsc/ngtsc_spec.ts
index 377558555e..b613f5ee9b 100644
--- a/packages/compiler-cli/test/ngtsc/ngtsc_spec.ts
+++ b/packages/compiler-cli/test/ngtsc/ngtsc_spec.ts
@@ -7493,16 +7493,20 @@ export const Foo = Foo__PRE_R3__;
            expect(diags.length).toBe(0);
          });
 
-      it('should error when an undecorated class with a non-trivial constructor in a declaration file is provided via useClass',
-         () => {
-           env.write('node_modules/@angular/core/testing/index.d.ts', `
+      // TODO(alxhub): this test never worked correctly, as it used to declare a constructor with a
+      // body, which real declaration files don't have. Without the body, the ReflectionHost used to
+      // not return any constructor data, preventing an error from showing. That bug was fixed, but
+      // the error for declaration files is disabled until g3 can be updated.
+      xit('should error when an undecorated class with a non-trivial constructor in a declaration file is provided via useClass',
+          () => {
+            env.write('node_modules/@angular/core/testing/index.d.ts', `
             export declare class NgZone {}
 
             export declare class Testability {
-              constructor(ngZone: NgZone) {}
+              constructor(ngZone: NgZone);
             }
           `);
-           env.write('test.ts', `
+            env.write('test.ts', `
             import {NgModule, Injectable} from '@angular/core';
             import {Testability} from '@angular/core/testing';
 
@@ -7515,10 +7519,10 @@ export const Foo = Foo__PRE_R3__;
             export class SomeModule {}
           `);
 
-           const diags = env.driveDiagnostics();
-           expect(diags.length).toBe(1);
-           expect(diags[0].messageText).toContain('cannot be created via dependency injection');
-         });
+            const diags = env.driveDiagnostics();
+            expect(diags.length).toBe(1);
+            expect(diags[0].messageText).toContain('cannot be created via dependency injection');
+          });
 
       it('should not error when an class with a factory definition and a non-trivial constructor in a declaration file is provided via useClass',
          () => {
@@ -7529,7 +7533,7 @@ export const Foo = Foo__PRE_R3__;
 
             export declare class Testability {
               static ɵfac: i0.ɵɵFactoryDef<Testability, never>;
-              constructor(ngZone: NgZone) {}
+              constructor(ngZone: NgZone);
             }
           `);
            env.write('test.ts', `