fix

src/Compilers/CSharp/Portable/Parser/LanguageParser.cs

@@ -11853,6 +11853,7 @@ ExpressionSyntax parseWhenNotNull(ExpressionSyntax expr)
                     // For example, 'a?.b!.c' should be a cond-access whose RHS is '.b!.c',
                     // while 'a?.b!' should be a suppression-expr containing a cond-access 'a?.b'.
                     using var beforeSuppressionsResetPoint = GetDisposableResetPoint(resetOnDispose: false);
+                    var expressionBeforeSuppressions = expr;
 
                     while (this.CurrentToken.Kind == SyntaxKind.ExclamationToken)
                         expr = _syntaxFactory.PostfixUnaryExpression(SyntaxKind.SuppressNullableWarningExpression, expr, EatToken());
@@ -11864,6 +11865,11 @@ ExpressionSyntax parseWhenNotNull(ExpressionSyntax expr)
                         continue;
                     }
 
+                    // A trailing cond-access or assignment is effectively the "end" of the current cond-access node.
+                    // Due to right-associativity, everything that follows will be included in the child node.
+                    // e.g. 'a?.b?.c' parses as '(a) ?. (.b?.c)'
+                    // e.g. 'a?.b = c?.d = e?.f' parses as 'a?.b = (c?.d = e?.f)'
+
                     // a?.b?.c
                     // a?.b!?.c
                     if (TryParseConditionalAccessExpression(expr, out var conditionalAccess))
@@ -11878,9 +11884,9 @@ ExpressionSyntax parseWhenNotNull(ExpressionSyntax expr)
                     }
 
                     // End of the cond-access.
-                    // Any '!' suppressions which followed this are a parent of the current cond-access, not a child of it.
+                    // Any '!' suppressions which followed this are a parent of the cond-access, not a child of it.
                     beforeSuppressionsResetPoint.Reset();
-                    return expr;
+                    return expressionBeforeSuppressions;
                 }
             }
 

src/Compilers/CSharp/Test/Syntax/Parsing/SuppressNullableWarningExpressionParsingTests.cs

@@ -650,6 +650,46 @@ public void ConditionalAccess_07()
             EOF();
         }
 
+        [Fact, WorkItem(47712, "https://github.com/dotnet/roslyn/pull/47712")]
+        public void ConditionalAccess_09()
+        {
+            UsingNode("x?.y?.z!");
+
+            N(SyntaxKind.SuppressNullableWarningExpression);
+            {
+                N(SyntaxKind.ConditionalAccessExpression);
+                {
+                    N(SyntaxKind.IdentifierName);
+                    {
+                        N(SyntaxKind.IdentifierToken, "x");
+                    }
+                    N(SyntaxKind.QuestionToken);
+                    N(SyntaxKind.ConditionalAccessExpression);
+                    {
+                        N(SyntaxKind.MemberBindingExpression);
+                        {
+                            N(SyntaxKind.DotToken);
+                            N(SyntaxKind.IdentifierName);
+                            {
+                                N(SyntaxKind.IdentifierToken, "y");
+                            }
+                        }
+                        N(SyntaxKind.QuestionToken);
+                        N(SyntaxKind.MemberBindingExpression);
+                        {
+                            N(SyntaxKind.DotToken);
+                            N(SyntaxKind.IdentifierName);
+                            {
+                                N(SyntaxKind.IdentifierToken, "z");
+                            }
+                        }
+                    }
+                }
+                N(SyntaxKind.ExclamationToken);
+            }
+            EOF();
+        }
+
         [Fact, WorkItem(47712, "https://github.com/dotnet/roslyn/pull/47712")]
         public void ConditionalAccess_ElementAccess()
         {