diff --git a/packages/compiler-cli/src/ngtsc/typecheck/src/diagnostics.ts b/packages/compiler-cli/src/ngtsc/typecheck/src/diagnostics.ts
index 3ed958274b..4e8b6f344c 100644
--- a/packages/compiler-cli/src/ngtsc/typecheck/src/diagnostics.ts
+++ b/packages/compiler-cli/src/ngtsc/typecheck/src/diagnostics.ts
@@ -46,6 +46,16 @@ export function wrapForDiagnostics(expr: ts.Expression): ts.Expression {
   return ts.createParen(expr);
 }
 
+const IGNORE_MARKER = 'ignore';
+
+/**
+ * Adds a marker to the node that signifies that any errors within the node should not be reported.
+ */
+export function ignoreDiagnostics(node: ts.Node): void {
+  ts.addSyntheticTrailingComment(
+      node, ts.SyntaxKind.MultiLineCommentTrivia, IGNORE_MARKER, /* hasTrailingNewLine */ false);
+}
+
 /**
  * Adds a synthetic comment to the expression that represents the parse span of the provided node.
  * This comment can later be retrieved as trivia of a node to recover original source locations.
@@ -214,17 +224,20 @@ interface SourceLocation {
   span: AbsoluteSourceSpan;
 }
 
+/**
+ * Traverses up the AST starting from the given node to extract the source location from comments
+ * that have been emitted into the TCB. If the node does not exist within a TCB, or if an ignore
+ * marker comment is found up the tree, this function returns null.
+ */
 function findSourceLocation(node: ts.Node, sourceFile: ts.SourceFile): SourceLocation|null {
   // Search for comments until the TCB's function declaration is encountered.
   while (node !== undefined && !ts.isFunctionDeclaration(node)) {
-    const span =
-        ts.forEachTrailingCommentRange(sourceFile.text, node.getEnd(), (pos, end, kind) => {
-          if (kind !== ts.SyntaxKind.MultiLineCommentTrivia) {
-            return null;
-          }
-          const commentText = sourceFile.text.substring(pos, end);
-          return parseSourceSpanComment(commentText);
-        }) || null;
+    if (hasIgnoreMarker(node, sourceFile)) {
+      // There's an ignore marker on this node, so the diagnostic should not be reported.
+      return null;
+    }
+
+    const span = readSpanComment(sourceFile, node);
     if (span !== null) {
       // Once the positional information has been extracted, search further up the TCB to extract
       // the unique id that is attached with the TCB's function declaration.
@@ -243,17 +256,21 @@ function findSourceLocation(node: ts.Node, sourceFile: ts.SourceFile): SourceLoc
 
 function getTemplateId(node: ts.Node, sourceFile: ts.SourceFile): TemplateId|null {
   // Walk up to the function declaration of the TCB, the file information is attached there.
-  let tcb = node;
-  while (!ts.isFunctionDeclaration(tcb)) {
-    tcb = tcb.parent;
+  while (!ts.isFunctionDeclaration(node)) {
+    if (hasIgnoreMarker(node, sourceFile)) {
+      // There's an ignore marker on this node, so the diagnostic should not be reported.
+      return null;
+    }
+    node = node.parent;
 
     // Bail once we have reached the root.
-    if (tcb === undefined) {
+    if (node === undefined) {
       return null;
     }
   }
 
-  return ts.forEachLeadingCommentRange(sourceFile.text, tcb.getFullStart(), (pos, end, kind) => {
+  const start = node.getFullStart();
+  return ts.forEachLeadingCommentRange(sourceFile.text, start, (pos, end, kind) => {
     if (kind !== ts.SyntaxKind.MultiLineCommentTrivia) {
       return null;
     }
@@ -262,13 +279,29 @@ function getTemplateId(node: ts.Node, sourceFile: ts.SourceFile): TemplateId|nul
   }) as TemplateId || null;
 }
 
-const parseSpanComment = /^\/\*(\d+),(\d+)\*\/$/;
+const parseSpanComment = /^(\d+),(\d+)$/;
 
-function parseSourceSpanComment(commentText: string): AbsoluteSourceSpan|null {
-  const match = commentText.match(parseSpanComment);
-  if (match === null) {
-    return null;
-  }
+function readSpanComment(sourceFile: ts.SourceFile, node: ts.Node): AbsoluteSourceSpan|null {
+  return ts.forEachTrailingCommentRange(sourceFile.text, node.getEnd(), (pos, end, kind) => {
+    if (kind !== ts.SyntaxKind.MultiLineCommentTrivia) {
+      return null;
+    }
+    const commentText = sourceFile.text.substring(pos + 2, end - 2);
+    const match = commentText.match(parseSpanComment);
+    if (match === null) {
+      return null;
+    }
 
-  return new AbsoluteSourceSpan(+match[1], +match[2]);
+    return new AbsoluteSourceSpan(+match[1], +match[2]);
+  }) || null;
+}
+
+function hasIgnoreMarker(node: ts.Node, sourceFile: ts.SourceFile): boolean {
+  return ts.forEachTrailingCommentRange(sourceFile.text, node.getEnd(), (pos, end, kind) => {
+    if (kind !== ts.SyntaxKind.MultiLineCommentTrivia) {
+      return null;
+    }
+    const commentText = sourceFile.text.substring(pos + 2, end - 2);
+    return commentText === IGNORE_MARKER;
+  }) === true;
 }
diff --git a/packages/compiler-cli/src/ngtsc/typecheck/src/expression.ts b/packages/compiler-cli/src/ngtsc/typecheck/src/expression.ts
index 99a6365175..2bb19db850 100644
--- a/packages/compiler-cli/src/ngtsc/typecheck/src/expression.ts
+++ b/packages/compiler-cli/src/ngtsc/typecheck/src/expression.ts
@@ -10,7 +10,7 @@ import {AST, ASTWithSource, AstVisitor, Binary, BindingPipe, Chain, Conditional,
 import * as ts from 'typescript';
 
 import {TypeCheckingConfig} from './api';
-import {addParseSpanInfo, wrapForDiagnostics} from './diagnostics';
+import {addParseSpanInfo, ignoreDiagnostics, wrapForDiagnostics} from './diagnostics';
 
 export const NULL_AS_ANY =
     ts.createAsExpression(ts.createNull(), ts.createKeywordTypeNode(ts.SyntaxKind.AnyKeyword));
@@ -222,11 +222,13 @@ class AstTranslator implements AstVisitor {
     // See the comment in SafePropertyRead above for an explanation of the need for the non-null
     // assertion here.
     const receiver = wrapForDiagnostics(this.translate(ast.receiver));
+    const guard = ts.getMutableClone(receiver);
+    ignoreDiagnostics(guard);
     const method = ts.createPropertyAccess(ts.createNonNullExpression(receiver), ast.name);
     const args = ast.args.map(expr => this.translate(expr));
     const expr = ts.createCall(method, undefined, args);
     const whenNull = this.config.strictSafeNavigationTypes ? UNDEFINED : NULL_AS_ANY;
-    const node = safeTernary(receiver, expr, whenNull);
+    const node = safeTernary(guard, expr, whenNull);
     addParseSpanInfo(node, ast.sourceSpan);
     return node;
   }
@@ -237,9 +239,11 @@ class AstTranslator implements AstVisitor {
     // assertion is necessary because in practice 'a' may be a method call expression, which won't
     // have a narrowed type when repeated in the ternary true branch.
     const receiver = wrapForDiagnostics(this.translate(ast.receiver));
+    const guard = ts.getMutableClone(receiver);
+    ignoreDiagnostics(guard);
     const expr = ts.createPropertyAccess(ts.createNonNullExpression(receiver), ast.name);
     const whenNull = this.config.strictSafeNavigationTypes ? UNDEFINED : NULL_AS_ANY;
-    const node = safeTernary(receiver, expr, whenNull);
+    const node = safeTernary(guard, expr, whenNull);
     addParseSpanInfo(node, ast.sourceSpan);
     return node;
   }
diff --git a/packages/compiler-cli/src/ngtsc/typecheck/src/type_check_block.ts b/packages/compiler-cli/src/ngtsc/typecheck/src/type_check_block.ts
index b358ef3300..a71944c421 100644
--- a/packages/compiler-cli/src/ngtsc/typecheck/src/type_check_block.ts
+++ b/packages/compiler-cli/src/ngtsc/typecheck/src/type_check_block.ts
@@ -13,7 +13,7 @@ import {Reference} from '../../imports';
 import {ClassDeclaration} from '../../reflection';
 
 import {TemplateId, TypeCheckBlockMetadata, TypeCheckableDirectiveMeta} from './api';
-import {addParseSpanInfo, addTemplateId, wrapForDiagnostics} from './diagnostics';
+import {addParseSpanInfo, addTemplateId, ignoreDiagnostics, wrapForDiagnostics} from './diagnostics';
 import {DomSchemaChecker} from './dom';
 import {Environment} from './environment';
 import {NULL_AS_ANY, astToTypescript} from './expression';
@@ -217,6 +217,10 @@ class TcbTemplateBodyOp extends TcbOp {
             // If there is such a binding, generate an expression for it.
             const expr = tcbExpression(boundInput.value, this.tcb, this.scope);
 
+            // The expression has already been checked in the type constructor invocation, so
+            // it should be ignored when used within a template guard.
+            ignoreDiagnostics(expr);
+
             if (guard.type === 'binding') {
               // Use the binding expression itself as guard.
               directiveGuards.push(expr);
diff --git a/packages/compiler-cli/src/ngtsc/typecheck/test/diagnostics_spec.ts b/packages/compiler-cli/src/ngtsc/typecheck/test/diagnostics_spec.ts
index b00c2efd65..1c281971de 100644
--- a/packages/compiler-cli/src/ngtsc/typecheck/test/diagnostics_spec.ts
+++ b/packages/compiler-cli/src/ngtsc/typecheck/test/diagnostics_spec.ts
@@ -43,7 +43,7 @@ runInEachFileSystem(() => {
           `<div *ngFor="let person of persons; let idx=index">{{ render(idx) }}</div>`, `
         class TestComponent {
           persons: {}[];
-          
+
           render(input: string): string { return input; }
         }`,
           [ngForDeclaration()], [ngForDts()]);
@@ -58,7 +58,7 @@ runInEachFileSystem(() => {
           `<div *ngFor="let person of persons;">{{ render(person.namme) }}</div>`, `
         class TestComponent {
           persons: any;
-          
+
           render(input: string): string { return input; }
         }`,
           [ngForDeclaration()], [ngForDts()]);
@@ -194,6 +194,46 @@ runInEachFileSystem(() => {
       ]);
     });
 
+    it('does not repeat diagnostics for errors within LHS of safe-navigation operator', () => {
+      const messages = diagnose(`{{ personn?.name }} {{ personn?.getName() }}`, `
+         class TestComponent {
+           person: {
+             name: string;
+             getName: () => string;
+           } | null;
+         }`);
+
+      expect(messages).toEqual([
+        `synthetic.html(1, 4): Property 'personn' does not exist on type 'TestComponent'. Did you mean 'person'?`,
+        `synthetic.html(1, 24): Property 'personn' does not exist on type 'TestComponent'. Did you mean 'person'?`,
+      ]);
+    });
+
+    it('does not repeat diagnostics for errors used in template guard expressions', () => {
+      const messages = diagnose(
+          `<div *guard="personn.name"></div>`, `
+          class GuardDir {
+            static ngTemplateGuard_guard: 'binding';
+          }
+
+          class TestComponent {
+            person: {
+              name: string;
+            };
+          }`,
+          [{
+            type: 'directive',
+            name: 'GuardDir',
+            selector: '[guard]',
+            inputs: {'guard': 'guard'},
+            ngTemplateGuards: [{inputName: 'guard', type: 'binding'}]
+          }]);
+
+      expect(messages).toEqual([
+        `synthetic.html(1, 14): Property 'personn' does not exist on type 'TestComponent'. Did you mean 'person'?`,
+      ]);
+    });
+
     it('does not produce diagnostics for user code', () => {
       const messages = diagnose(`{{ person.name }}`, `
       class TestComponent {
@@ -313,7 +353,7 @@ runInEachFileSystem(() => {
 <div>
   <img [src]="srcc"
        [height]="heihgt">
-</div>    
+</div>
 `,
           `
 class TestComponent {
diff --git a/packages/compiler-cli/src/ngtsc/typecheck/test/span_comments_spec.ts b/packages/compiler-cli/src/ngtsc/typecheck/test/span_comments_spec.ts
index 81627c40ce..35c3de00a6 100644
--- a/packages/compiler-cli/src/ngtsc/typecheck/test/span_comments_spec.ts
+++ b/packages/compiler-cli/src/ngtsc/typecheck/test/span_comments_spec.ts
@@ -97,14 +97,15 @@ describe('type check blocks diagnostics', () => {
     it('should annotate safe property access', () => {
       const TEMPLATE = `{{ a?.b }}`;
       expect(tcbWithSpans(TEMPLATE))
-          .toContain('(((ctx).a /*3,4*/) != null ? ((ctx).a /*3,4*/)!.b : undefined) /*3,8*/;');
+          .toContain(
+              '(((ctx).a /*3,4*/) /*ignore*/ != null ? ((ctx).a /*3,4*/)!.b : undefined) /*3,8*/;');
     });
 
     it('should annotate safe method calls', () => {
       const TEMPLATE = `{{ a?.method(b) }}`;
       expect(tcbWithSpans(TEMPLATE))
           .toContain(
-              '(((ctx).a /*3,4*/) != null ? ((ctx).a /*3,4*/)!.method((ctx).b /*13,14*/) : undefined) /*3,16*/;');
+              '(((ctx).a /*3,4*/) /*ignore*/ != null ? ((ctx).a /*3,4*/)!.method((ctx).b /*13,14*/) : undefined) /*3,16*/;');
     });
 
     it('should annotate $any casts', () => {