fix(compiler): avoid emitting self importing factories

Fixes: #17389

packages/compiler-cli/src/compiler_host.ts

@@ -110,7 +110,7 @@ export class CompilerHost implements AotCompilerHost {
   fileNameToModuleName(importedFile: string, containingFile: string): string {
     // If a file does not yet exist (because we compile it later), we still need to
     // assume it exists it so that the `resolve` method works!
-    if (!this.context.fileExists(importedFile)) {
+    if (importedFile !== containingFile && !this.context.fileExists(importedFile)) {
       this.context.assumeFileExists(importedFile);
     }
 

packages/compiler/src/aot/compiler.ts

@@ -304,7 +304,10 @@ export class AotCompiler {
       }
       const arity = this._symbolResolver.getTypeArity(symbol) || 0;
       const {filePath, name, members} = this._symbolResolver.getImportAs(symbol) || symbol;
-      const moduleName = this._symbolResolver.fileNameToModuleName(filePath, genFilePath);
+      const importModule = this._symbolResolver.fileNameToModuleName(filePath, genFilePath);
+      const selfReference = this._symbolResolver.fileNameToModuleName(genFilePath, genFilePath);
+      const moduleName = importModule === selfReference ? null : importModule;
+
       // If we are in a type expression that refers to a generic type then supply
       // the required type parameters. If there were not enough type parameters
       // supplied, supply any as the type. Outside a type expression the reference

packages/compiler/src/aot/static_symbol_resolver.ts

@@ -162,9 +162,6 @@ export class StaticSymbolResolver {
    * Converts a file path to a module name that can be used as an `import`.
    */
   fileNameToModuleName(importedFilePath: string, containingFilePath: string): string|null {
-    if (importedFilePath === containingFilePath) {
-      return null;
-    }
     return this.knownFileNameToModuleNames.get(importedFilePath) ||
         this.host.fileNameToModuleName(importedFilePath, containingFilePath);
   }

packages/compiler/test/aot/compiler_spec.ts

@@ -233,6 +233,37 @@ describe('compiler (unbundled Angular)', () => {
       };
       compile([FILES, angularFiles], {postCompile: expectNoDiagnostics});
     });
+
+    it('should not contain a self import in factory', () => {
+      const FILES: MockDirectory = {
+        app: {
+          'app.ts': `
+                import {Component, NgModule} from '@angular/core';
+
+                interface Person { name: string; }
+
+                @Component({
+                  selector: 'my-comp',
+                  template: '{{person.name}}'
+                })
+                export class MyComp {
+                  person: Person;
+                }
+
+                @NgModule({
+                  declarations: [MyComp]
+                })
+                export class MyModule {}
+              `
+        }
+      };
+      compile([FILES, angularFiles], {
+        postCompile: program => {
+          const factorySource = program.getSourceFile('/app/app.ngfactory.ts');
+          expect(factorySource.text).not.toContain('\'/app/app.ngfactory\'');
+        }
+      });
+    });
   });
 
   it('should add the preamble to generated files', () => {