diff --git a/packages/compiler-cli/src/ngtsc/program.ts b/packages/compiler-cli/src/ngtsc/program.ts
index a145cc98ba..57fb55efe7 100644
--- a/packages/compiler-cli/src/ngtsc/program.ts
+++ b/packages/compiler-cli/src/ngtsc/program.ts
@@ -37,6 +37,7 @@ import {getRootDirs, isDtsPath} from './util/src/typescript';
 
 export class NgtscProgram implements api.Program {
   private tsProgram: ts.Program;
+  private reuseTsProgram: ts.Program;
   private resourceManager: HostResourceLoader;
   private compilation: IvyCompilation|undefined = undefined;
   private factoryToSourceInfo: Map<string, FactoryInfo>|null = null;
@@ -68,7 +69,7 @@ export class NgtscProgram implements api.Program {
 
   constructor(
       rootNames: ReadonlyArray<string>, private options: api.CompilerOptions,
-      host: api.CompilerHost, oldProgram?: api.Program) {
+      host: api.CompilerHost, oldProgram?: NgtscProgram) {
     if (shouldEnablePerfTracing(options)) {
       this.perfTracker = PerfTracker.zeroedToNow();
       this.perfRecorder = this.perfTracker;
@@ -146,7 +147,8 @@ export class NgtscProgram implements api.Program {
     }
 
     this.tsProgram =
-        ts.createProgram(rootFiles, options, this.host, oldProgram && oldProgram.getTsProgram());
+        ts.createProgram(rootFiles, options, this.host, oldProgram && oldProgram.reuseTsProgram);
+    this.reuseTsProgram = this.tsProgram;
 
     this.entryPoint = entryPoint !== null ? this.tsProgram.getSourceFile(entryPoint) || null : null;
     this.moduleResolver = new ModuleResolver(this.tsProgram, options, this.host);
@@ -155,9 +157,8 @@ export class NgtscProgram implements api.Program {
     if (oldProgram === undefined) {
       this.incrementalState = IncrementalState.fresh();
     } else {
-      const oldNgtscProgram = oldProgram as NgtscProgram;
       this.incrementalState = IncrementalState.reconcile(
-          oldNgtscProgram.incrementalState, oldNgtscProgram.tsProgram, this.tsProgram);
+          oldProgram.incrementalState, oldProgram.reuseTsProgram, this.tsProgram);
     }
   }
 
@@ -415,8 +416,10 @@ export class NgtscProgram implements api.Program {
 
     // Get the diagnostics.
     const typeCheckSpan = this.perfRecorder.start('typeCheckDiagnostics');
-    const diagnostics = ctx.calculateTemplateDiagnostics(this.tsProgram, this.host, this.options);
+    const {diagnostics, program} =
+        ctx.calculateTemplateDiagnostics(this.tsProgram, this.host, this.options);
     this.perfRecorder.stop(typeCheckSpan);
+    this.reuseTsProgram = program;
 
     return diagnostics;
   }
diff --git a/packages/compiler-cli/src/ngtsc/typecheck/src/context.ts b/packages/compiler-cli/src/ngtsc/typecheck/src/context.ts
index 6d545eb1a8..e6571e73ce 100644
--- a/packages/compiler-cli/src/ngtsc/typecheck/src/context.ts
+++ b/packages/compiler-cli/src/ngtsc/typecheck/src/context.ts
@@ -164,7 +164,10 @@ export class TypeCheckContext {
 
   calculateTemplateDiagnostics(
       originalProgram: ts.Program, originalHost: ts.CompilerHost,
-      originalOptions: ts.CompilerOptions): ts.Diagnostic[] {
+      originalOptions: ts.CompilerOptions): {
+    diagnostics: ts.Diagnostic[],
+    program: ts.Program,
+  } {
     const typeCheckSf = this.typeCheckFile.render();
     // First, build the map of original source files.
     const sfMap = new Map<string, ts.SourceFile>();
@@ -191,17 +194,23 @@ export class TypeCheckContext {
       diagnostics.push(...typeCheckProgram.getSemanticDiagnostics(sf));
     }
 
-    return diagnostics.filter((diag: ts.Diagnostic): boolean => {
-      if (diag.code === 6133 /* $var is declared but its value is never read. */) {
-        return false;
-      } else if (diag.code === 6199 /* All variables are unused. */) {
-        return false;
-      } else if (
-          diag.code === 2695 /* Left side of comma operator is unused and has no side effects. */) {
-        return false;
-      }
-      return true;
-    });
+    return {
+      diagnostics: diagnostics.filter(
+          (diag: ts.Diagnostic):
+              boolean => {
+                if (diag.code === 6133 /* $var is declared but its value is never read. */) {
+                  return false;
+                } else if (diag.code === 6199 /* All variables are unused. */) {
+                  return false;
+                } else if (
+                    diag.code ===
+                    2695 /* Left side of comma operator is unused and has no side effects. */) {
+                  return false;
+                }
+                return true;
+              }),
+      program: typeCheckProgram,
+    };
   }
 
   private addInlineTypeCheckBlock(
diff --git a/packages/compiler-cli/src/transformers/program.ts b/packages/compiler-cli/src/transformers/program.ts
index f14c259466..0935a87b30 100644
--- a/packages/compiler-cli/src/transformers/program.ts
+++ b/packages/compiler-cli/src/transformers/program.ts
@@ -899,7 +899,7 @@ export function createProgram({rootNames, options, host, oldProgram}: {
   host: CompilerHost, oldProgram?: Program
 }): Program {
   if (options.enableIvy === true) {
-    return new NgtscProgram(rootNames, options, host, oldProgram);
+    return new NgtscProgram(rootNames, options, host, oldProgram as NgtscProgram);
   } else if (options.enableIvy === 'tsc') {
     return new TscPassThroughProgram(rootNames, options, host, oldProgram);
   }
diff --git a/packages/compiler-cli/test/ngtsc/incremental_spec.ts b/packages/compiler-cli/test/ngtsc/incremental_spec.ts
index 5092ea4d86..f78fbe1b31 100644
--- a/packages/compiler-cli/test/ngtsc/incremental_spec.ts
+++ b/packages/compiler-cli/test/ngtsc/incremental_spec.ts
@@ -44,4 +44,14 @@ describe('ngtsc incremental compilation', () => {
     expect(written).toContain('/test.js');
     expect(written).not.toContain('/service.js');
   });
+
+  it('should compile incrementally with template type-checking turned on', () => {
+    env.tsconfig({ivyTemplateTypeCheck: true});
+    env.write('main.ts', 'export class Foo {}');
+    env.driveMain();
+    env.invalidateCachedFile('main.ts');
+    env.driveMain();
+    // If program reuse were configured incorrectly (as was responsible for
+    // https://github.com/angular/angular/issues/30079), this would have crashed.
+  });
 });
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