fix(compiler-cli): use any when checking field interface conformance

Switches to checking against `FormValueControl<any>` instead of `FormValueControl<unknown>` when checking whether custom controls conform to the interface.

Fixes #64946.

(cherry picked from commit 4d07785)

Author: crisbeto

packages/compiler-cli/src/ngtsc/typecheck/src/type_check_block.ts

@@ -975,7 +975,7 @@ class TcbCustomFieldDirectiveTypeOp extends TcbFieldDirectiveTypeBaseOp {
     const id = this.tcb.allocateId();
     const targetType = ts.factory.createTypeReferenceNode(
       targetTypeRef.typeName,
-      isCheckbox ? undefined : [ts.factory.createKeywordTypeNode(ts.SyntaxKind.UnknownKeyword)],
+      isCheckbox ? undefined : [ts.factory.createKeywordTypeNode(ts.SyntaxKind.AnyKeyword)],
     );
     this.scope.addStatement(tsDeclareVariable(id, targetType));
 

packages/compiler-cli/src/ngtsc/typecheck/test/type_check_block_spec.ts

@@ -2658,7 +2658,7 @@ describe('type check blocks', () => {
       expect(block).toContain(
         'var _t1 = null! as i0.Field<i1.ɵExtractFormControlValue<i0.CustomControl>>;',
       );
-      expect(block).toContain('var _t2 = null! as i2.FormValueControl<unknown>;');
+      expect(block).toContain('var _t2 = null! as i2.FormValueControl<any>;');
       expect(block).toContain('if (_t2) _t2 = null! as i0.CustomControl;');
       expect(block).toContain('_t1.field = (((this).f));');
     });

packages/compiler-cli/test/ngtsc/signal_forms_spec.ts

@@ -19,7 +19,11 @@ runInEachFileSystem(() => {
 
     beforeEach(() => {
       env = NgtscTestEnvironment.setup(testFiles);
-      env.tsconfig({strictTemplates: true});
+      env.tsconfig({
+        // This is the default in Angular apps so we enable it to ensure consistent behavior.
+        strict: true,
+        strictTemplates: true,
+      });
     });
 
     function extractMessage(diag: ts.Diagnostic) {
@@ -191,6 +195,33 @@ runInEachFileSystem(() => {
       );
     });
 
+    it('should not report a custom control that conforms to `FormValueControl`', () => {
+      env.write(
+        'test.ts',
+        `
+          import {Component, signal, model} from '@angular/core';
+          import {Field, form, FormValueControl} from '@angular/forms/signals';
+
+          @Component({ selector: 'string-control', template: '' })
+          class StringControl implements FormValueControl<string> {
+            value = model('');
+          }
+
+          @Component({
+            selector: 'app-root',
+            imports: [Field, StringControl],
+            template: '<string-control [field]="field" />',
+          })
+          class App {
+            field = form(signal(''));
+          }
+        `,
+      );
+
+      const diags = env.driveDiagnostics();
+      expect(diags.length).toBe(0);
+    });
+
     it('should report unsupported property bindings on a field', () => {
       env.write(
         'test.ts',
@@ -290,10 +321,10 @@ runInEachFileSystem(() => {
       const diags = env.driveDiagnostics();
       expect(diags.length).toBe(1);
       expect(extractMessage(diags[0])).toBe(
-        `Type 'UserControl' is not assignable to type 'FormValueControl<unknown>'.`,
+        `Type 'UserControl' is not assignable to type 'FormValueControl<any>'.`,
       );
       expect((diags[0].messageText as ts.DiagnosticMessageChain).next?.[0].messageText).toBe(
-        `Types of property 'required' are incompatible.`,
+        `The types of 'required[SIGNAL].transformFn' are incompatible between these types.`,
       );
     });
 
@@ -326,7 +357,7 @@ runInEachFileSystem(() => {
         `Type 'UserControl' is not assignable to type 'FormCheckboxControl'.`,
       );
       expect((diags[0].messageText as ts.DiagnosticMessageChain).next?.[0].messageText).toBe(
-        `Types of property 'required' are incompatible.`,
+        `The types of 'required[SIGNAL].transformFn' are incompatible between these types.`,
       );
     });
   });