Update ExplicitNumberDeclarationAnalyzer to handle out var and foreach

[google-labs-jules]

This PR updates the ExplicitNumberDeclarationAnalyzer (SMA8001) to correctly identify and warn against the use of var for numeric primitive types in additional contexts. Specifically, it now handles:

• out var declarations (e.g., TryGetValue(out var value)).
• foreach loops with var (e.g., foreach (var x in collection)).
• Deconstruction declarations with var (e.g., var (a, b) = ...).
• Nested deconstructions and deconstructions within foreach loops.

The implementation was refactored to share common reporting logic and recursively handle tuple deconstructions. Unit tests have been expanded to verify these new scenarios.

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PR created automatically by Jules for task 1733819396258710820 started by @sator-imaging

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Walkthrough

ExplicitNumberDeclarationAnalyzer is extended to detect primitive-number var usage in declaration expressions (out var, tuple deconstruction) and foreach statements. Reporting logic is extracted into a shared ReportIfPrimitiveNumber helper. A new test asserts six diagnostics across all added patterns.

Changes

SMA8001 Analyzer Extension for Additional var Patterns

Layer / File(s)	Summary
New var pattern handlers and shared helper src/analysis/Analyzers/ExplicitNumberDeclarationAnalyzer.cs	Initialize registers handlers for DeclarationExpressionSyntax and ForEachStatementSyntax. AnalyzeDeclarationExpression handles single and parenthesized variable designations, ReportRecursive traverses nested tuples, AnalyzeForEachStatement checks foreach var type, and ReportIfPrimitiveNumber is introduced as a shared helper that validates ILocalSymbol and emits SMA8001. AnalyzeVariableDeclaration is updated to delegate to this helper.
Violation test for out var, foreach, and tuple deconstruction test/AnalyzerTests/SMA8001_ExplicitNumberDeclarationAnalyzerTests.cs	Adds SMA8001_Violation_OtherVarDeclarationsWithPrimitiveNumbers, which supplies an inline C# snippet with out var, foreach, and tuple deconstruction patterns and asserts six SMA8001 diagnostics with specific identifier names and source locations.

Estimated code review effort

3 (Moderate) | ~20 minutes

Finishing Touches

Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch update-explicit-number-analyzer-1733819396258710820

Simplify code

• Create PR with simplified code
• Commit simplified code in branch update-explicit-number-analyzer-1733819396258710820

[coderabbitai]

Nitpick comments (1)

test/AnalyzerTests/SMA8001_ExplicitNumberDeclarationAnalyzerTests.cs (1)

159-196: 💤 Low value

Consider adding test coverage for edge cases.

The test comprehensively covers the main scenarios. Consider adding optional test cases for:

• Deeply nested tuple deconstruction: var ((a, b), c) = ((1, 2), 3);
• Discards in tuple deconstruction: var (_, b) = (1, 2); (should only flag b if it's a primitive number)

These edge cases would verify that the recursive tuple handling and null symbol checks work correctly in all scenarios.

Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@test/AnalyzerTests/SMA8001_ExplicitNumberDeclarationAnalyzerTests.cs` around
lines 159 - 196, The test method
SMA8001_Violation_OtherVarDeclarationsWithPrimitiveNumbers lacks coverage for
edge cases involving deeply nested tuple deconstruction and discard patterns.
Add test cases within the test string variable that include deeply nested tuple
deconstruction syntax (such as var ((a, b), c) = ((1, 2), 3);) and discard
patterns in tuple deconstruction (such as var (_, b) = (1, 2);), then add the
corresponding expected diagnostic assertions to verify that the analyzer
correctly handles recursive tuple handling and only flags non-discard variables
when they involve primitive numbers.

Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In `@test/AnalyzerTests/SMA8001_ExplicitNumberDeclarationAnalyzerTests.cs`:
- Around line 159-196: The test method
SMA8001_Violation_OtherVarDeclarationsWithPrimitiveNumbers lacks coverage for
edge cases involving deeply nested tuple deconstruction and discard patterns.
Add test cases within the test string variable that include deeply nested tuple
deconstruction syntax (such as var ((a, b), c) = ((1, 2), 3);) and discard
patterns in tuple deconstruction (such as var (_, b) = (1, 2);), then add the
corresponding expected diagnostic assertions to verify that the analyzer
correctly handles recursive tuple handling and only flags non-discard variables
when they involve primitive numbers.

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Review details

Additional comments (7)

src/analysis/Analyzers/ExplicitNumberDeclarationAnalyzer.cs (6)

34-35: LGTM!

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38-55: LGTM!

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80-93: LGTM!

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111-120: LGTM!

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57-78: No issues found. The project targets C# 9.0 (as configured in the project file), which fully supports the is not pattern used on line 65. The code is compatible and requires no changes.

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95-109: No issues found. Foreach with tuple deconstruction is correctly handled through the DeclarationExpression handler. When encountering foreach (var (x, y) in ...), the syntax tree contains a ForEachVariableStatementSyntax with a Variable property that is a DeclarationExpressionSyntax. This DeclarationExpressionSyntax triggers the AnalyzeDeclarationExpression handler, which detects the ParenthesizedVariableDesignationSyntax and delegates to ReportRecursive to recursively report all tuple variables. The test expectations at line 181 align with this behavior and will pass correctly.

test/AnalyzerTests/SMA8001_ExplicitNumberDeclarationAnalyzerTests.cs (1)

159-196: LGTM!