/dotnet:fix-warnings
Batch-fix analyzer warnings with category filtering, preview mode, and interactive review options.
Arguments
Parse arguments from $ARGUMENTS:
| Flag | Description | Default |
|------|-------------|---------|
| --category <cat> | Fix specific category (see below) | All fixable |
| --severity <level> | Minimum severity (error, warning, suggestion, hidden) | warning |
| --preview | Show changes without applying | false |
| --interactive | Review each fix before applying | false |
| --project <path> | Target specific project (fuzzy matching) | All projects |
Warning Categories
| Category | Description | Analyzer Prefix |
|----------|-------------|-----------------|
| style | Code style (IDE*) | IDE0001-IDE0999 |
| quality | Code quality (CA*) | CA1000-CA9999 |
| naming | Naming conventions | CA1700-CA1727, IDE1006 |
| performance | Performance issues | CA1800-CA1869 |
| security | Security concerns | CA2100-CA2399, CA3000-CA3147 |
| reliability | Reliability issues | CA2000-CA2099 |
| usage | API usage issues | CA2200-CA2249 |
| nullable | Nullable reference warnings | CS8600-CS8799 |
| async | Async/await issues | CA2007, CA2008, CS8892 |
Workflow
Step 1: Run Analyzers
Build with detailed diagnostics:
dotnet build --no-incremental -warnaserror:0 2>&1
Or use format for fixable warnings:
dotnet format analyzers --verify-no-changes --verbosity diagnostic
Step 2: Parse and Categorize Warnings
Group warnings by:
- Category (style, quality, naming, etc.)
- Severity (error, warning, suggestion)
- File location
- Fixability (auto-fixable vs manual)
Step 3: Present Summary
Analyzer Warnings Summary
Category Count Auto-fixable
─────────────────────────────────────
Style 42 38
Quality 15 8
Naming 7 7
Nullable 23 12
Performance 3 1
─────────────────────────────────────
Total 90 66
Files affected: 28
Run with --preview to see specific warnings.
Run without flags to fix all auto-fixable warnings.
Step 4: Preview Mode (--preview)
Show what would be changed:
Preview: Warnings to Fix
IDE0008 (Style): Use explicit type instead of 'var' (12 occurrences)
- src/MyApp/Services/UserService.cs:42
- src/MyApp/Services/UserService.cs:56
- src/MyApp/Controllers/ApiController.cs:23
... and 9 more
CA1062 (Quality): Validate arguments of public methods (5 occurrences)
- src/MyApp/Services/DataService.cs:18
- src/MyApp/Handlers/CommandHandler.cs:31
... and 3 more
CS8618 (Nullable): Non-nullable field not initialized (8 occurrences)
- src/MyApp/Models/User.cs:12
- src/MyApp/Models/Order.cs:8
... and 6 more
Total: 66 auto-fixable warnings across 28 files
Run without --preview to apply fixes.
Step 5: Apply Fixes
Automatic Mode (default):
# Fix all style warnings
dotnet format style
# Fix all analyzer warnings
dotnet format analyzers
# Fix whitespace
dotnet format whitespace
Category-specific:
# Fix only naming warnings
dotnet format analyzers --diagnostics=CA1700,CA1707,CA1708,CA1710,CA1711,CA1712,CA1713,CA1714,CA1715,CA1716,CA1717,CA1720,CA1721,CA1724,CA1725,CA1727,IDE1006
Interactive Mode (--interactive):
For each warning category:
Fix IDE0008: Use explicit type instead of 'var'? (12 occurrences)
Example:
Before: var service = new UserService();
After: UserService service = new UserService();
Options:
1. Fix all 12 occurrences
2. Skip this rule
3. Review each occurrence individually
Step 6: Validate
After fixes:
dotnet build --no-restore
Report any issues introduced by fixes.
Output Format
Summary Mode (no flags):
Fixing Analyzer Warnings...
Applied fixes:
Style (IDE*): 38 warnings fixed
Quality (CA*): 8 warnings fixed
Naming: 7 warnings fixed
Nullable: 12 warnings fixed
Remaining (not auto-fixable):
CA1062: 5 warnings - Validate arguments (manual review needed)
CA2000: 3 warnings - Dispose objects (manual review needed)
CS8604: 11 warnings - Possible null reference (context-dependent)
Files modified: 28
Build: Successful
Run with --category to fix specific categories.
Review remaining warnings manually or suppress with justification.
Interactive Mode:
Fixing Warnings Interactively
[1/5] IDE0008: Use explicit type (12 occurrences)
Fix all? [Y/n/s(kip)/r(eview)]
> Y
Fixed 12 occurrences
[2/5] CA1707: Remove underscores from member names (3 occurrences)
Fix all? [Y/n/s(kip)/r(eview)]
> r
1. _myField -> MyField in User.cs:15
Fix? [y/n] > y
2. Get_Data() -> GetData() in DataService.cs:42
Fix? [y/n] > n (skip - intentional convention)
3. API_VERSION -> ApiVersion in Constants.cs:8
Fix? [y/n] > y
Fixed 2 of 3 occurrences
... (continues for each category)
Summary:
Fixed: 52 warnings
Skipped: 14 warnings (user choice)
Build: Successful
Common Warning Fixes
| Warning | Auto-Fix | Manual Action |
|---------|----------|---------------|
| IDE0008 | Yes | Change var to explicit type |
| IDE0003 | Yes | Remove this. qualification |
| IDE0059 | Yes | Remove unnecessary assignment |
| CA1062 | Partial | Add null checks (context-dependent) |
| CA2000 | No | Add using or .Dispose() calls |
| CS8618 | Partial | Add = null! or required |
| CA1707 | Yes | Remove underscores |
| CA1716 | Yes | Rename to avoid keyword conflict |
Examples
# Fix all auto-fixable warnings
/dotnet:fix-warnings
# Preview without fixing
/dotnet:fix-warnings --preview
# Fix only style warnings
/dotnet:fix-warnings --category style
# Fix only naming issues
/dotnet:fix-warnings --category naming
# Interactive mode - review each fix
/dotnet:fix-warnings --interactive
# Fix warnings in specific project
/dotnet:fix-warnings --project MyApp.Api
# Fix only errors and warnings (skip suggestions)
/dotnet:fix-warnings --severity warning
Warnings That Cannot Be Auto-Fixed
Some warnings require manual review:
- CA2000 (Dispose): Context-dependent object lifetime
- CA1062 (Null check): May need different validation strategy
- CA2007 (ConfigureAwait): Library vs app decision
- CS8604 (Null flow): May need design change
For these, the command reports them but doesn't modify code.
Integration with .editorconfig
Respects .editorconfig settings:
# These rules will be applied during fix
dotnet_style_var_for_built_in_types = false:warning
dotnet_naming_rule.public_members_must_be_capitalized.severity = warning