Escape variable declarations named after C# keywords (#133)

[paulirwin]

Fixes #133.

Problem

TypeHelper.EscapeIdentifier was applied at identifier usages — NameExpressionVisitor, FieldAccessExpressionVisitor — and at parameters, but never at any declaration site. So a variable named after a C# keyword produced output that referenced an identifier it never declared:

using (InputStream in = new FileInputStream(dictionaryFile))  // not escaped
{
    Init(@in);                                                 // escaped
}

That C# does not compile. Seven sites were affected, all of the same shape.

Fix

Applied EscapeIdentifier at every declaration site:

Site	File
Local variables	ExpressionStatementVisitor.cs
Fields	FieldDeclarationVisitor.cs
try-with-resources declarations	TryStatementVisitor.cs
try (existingVar) resources (Java 9+)	TryStatementVisitor.cs
Catch parameters	TryStatementVisitor.cs
foreach variables	ForEachStatementVisitor.cs
for-loop init	ForStatementVisitor.cs

Two needed more than an added call:

ForEachStatementVisitor built a VariableDeclarator only to read Identifier.ValueText back off it, which strips the @ prefix. It now constructs the identifier token directly, dropping the pointless round trip.

ForStatementVisitor passed VariableDeclarator.toString() into SyntaxFactory.VariableDeclarator. That returns the name and its initializer ("i = 0"), while that overload treats the whole string as an identifier name — it happened to round-trip through the printer, which is why it worked. Escaping it blindly corrupts the output, so the declarator is now built from its parts: the escaped name plus the initializer visited through ExpressionVisitor, matching how every other declarator site works.

Testing

Written TDD — each test was added and confirmed failing before the corresponding fix. Eight new tests in EscapeIdentifierTests.cs cover local variables, fields, try-with-resources (both forms), catch parameters, foreach, for-loop init, and a multi-declarator for loop (int @base = 0, i = 1) asserting that only the keyword is escaped.

The ForStatementVisitor rewrite is a behavior change on a hot path, so coverage there matters beyond the unit tests: Resources/*.java contains dozens of classic for loops, and FullIntegrationTests Roslyn-compiles the generated C# and executes it. Those pass, which is what establishes the rewrite is faithful rather than merely printer-identical.

	Before	After
New escaping tests (8)	fail	pass
Full suite	256 pass	264 pass

Scope note

Only the first commit is #133 as filed. The for-loop, catch-clause, and try (existingVar) sites are the same class of bug, found while fixing it, and are split into their own commits — they drop cleanly onto a separate branch if you'd rather keep #133 narrow.

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