refactor(ivy): remove the tsc passthrough option (angular#32219)

This option makes ngc behave as tsc, and was originally implemented before
ngtsc existed. It was designed so we could build JIT-only versions of
Angular packages to begin testing Ivy early, and is not used at all in our
current setup.

PR Close angular#32219

packages/bazel/src/ngc-wrapped/index.ts

@@ -184,15 +184,10 @@ export function compile({allDepsCompiledWithBazel = true, compilerOpts, tsHost,
   }
 
   // Detect from compilerOpts whether the entrypoint is being invoked in Ivy mode.
-  const isInIvyMode = compilerOpts.enableIvy === 'ngtsc' || compilerOpts.enableIvy === 'tsc';
+  const isInIvyMode = compilerOpts.enableIvy === 'ngtsc';
 
   // Disable downleveling and Closure annotation if in Ivy mode.
   if (isInIvyMode) {
-    // In pass-through mode for TypeScript, we want to turn off decorator transpilation entirely.
-    // This causes ngc to be have exactly like tsc.
-    if (compilerOpts.enableIvy === 'tsc') {
-      compilerOpts.annotateForClosureCompiler = false;
-    }
     compilerOpts.annotationsAs = 'decorators';
   }
 

packages/compiler-cli/src/transformers/api.ts

@@ -196,11 +196,10 @@ export interface CompilerOptions extends ts.CompilerOptions {
    * `false` - run ngc normally
    * `true` - run the ngtsc compiler instead of the normal ngc compiler
    * `ngtsc` - alias for `true`
-   * `tsc` - behave like plain tsc as much as possible (used for testing JIT code)
    *
    * @publicApi
    */
-  enableIvy?: boolean|'ngtsc'|'tsc';
+  enableIvy?: boolean|'ngtsc';
 
   /** @internal */
   collectAllErrors?: boolean;

packages/compiler-cli/src/transformers/program.ts

@@ -27,7 +27,6 @@ import {getAngularEmitterTransformFactory} from './node_emitter_transform';
 import {PartialModuleMetadataTransformer} from './r3_metadata_transform';
 import {StripDecoratorsMetadataTransformer, getDecoratorStripTransformerFactory} from './r3_strip_decorators';
 import {getAngularClassTransformerFactory} from './r3_transform';
-import {TscPassThroughProgram} from './tsc_pass_through';
 import {DTS, GENERATED_FILES, StructureIsReused, TS, createMessageDiagnostic, isInRootDir, ngToTsDiagnostic, tsStructureIsReused, userError} from './util';
 
 
@@ -900,10 +899,9 @@ export function createProgram({rootNames, options, host, oldProgram}: {
 }): Program {
   if (options.enableIvy === true) {
     return new NgtscProgram(rootNames, options, host, oldProgram as NgtscProgram);
-  } else if (options.enableIvy === 'tsc') {
-    return new TscPassThroughProgram(rootNames, options, host, oldProgram);
+  } else {
+    return new AngularCompilerProgram(rootNames, options, host, oldProgram);
   }
-  return new AngularCompilerProgram(rootNames, options, host, oldProgram);
 }
 
 // Compute the AotCompiler options

packages/compiler/src/aot/compiler_options.ts

@@ -19,6 +19,6 @@ export interface AotCompilerOptions {
   fullTemplateTypeCheck?: boolean;
   allowEmptyCodegenFiles?: boolean;
   strictInjectionParameters?: boolean;
-  enableIvy?: boolean|'ngtsc'|'tsc';
+  enableIvy?: boolean|'ngtsc';
   createExternalSymbolFactoryReexports?: boolean;
 }