Summary

Multiple classes across the repository were throwing IndexOutOfRangeException with nameof(index) as the message parameter, resulting in an unhelpful error message of just "index" instead of the standard .NET exception message.

Changes

This PR updates all occurrences to use the parameterless IndexOutOfRangeException() constructor, which provides the default, user-friendly message: "Index was outside the bounds of the array."

Before:

throw new IndexOutOfRangeException(nameof(index));
// Exception message: "index"

After:

throw new IndexOutOfRangeException();
// Exception message: "Index was outside the bounds of the array."

Files Modified

Logging-related files:

• LoggerMessage.cs: Fixed 7 occurrences across different generic LogValues<T> classes
• LoggerMessageGenerator.Emitter.cs: Fixed 1 occurrence in the source generator template
• LogValuesFormatter.cs: Fixed 1 occurrence in the logging formatter
• FormattedLogValues.cs: Fixed 1 occurrence in formatted log values
• LoggerExtensionsTest.cs: Fixed 1 occurrence in test helper class
• HttpHeadersLogValue.cs: Fixed 1 occurrence in HTTP logging infrastructure
• Baseline test files: Updated 3 generated code baseline files to match the new output
• LoggerMessageTest.cs: Added comprehensive test to verify the exception message is proper

Other components:

• DesignerOptionService.cs: Fixed 1 occurrence in System.ComponentModel.TypeConverter

Testing

• All existing tests continue to pass (291 tests in Microsoft.Extensions.Logging.Tests, 184 tests in Microsoft.Extensions.Http.Tests)
• Added new test LogValues_OutOfRangeAccess_ThrowsIndexOutOfRangeExceptionWithDefaultMessage that validates the exception message for all LogValues variants (0-6 parameters)
• Manually verified the fix produces the expected error message

This is a minimal change that maintains backward compatibility (still throws IndexOutOfRangeException) while significantly improving the developer experience with a clear, descriptive error message across the entire codebase.

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.