/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