[matt-edmondson]

Fixes #158

What changed

TemplateRendering.WriteExpressionBody, which PropertyTemplate.ExpressionBodyFactory and AccessorKind.Expression share, now handles preprocessor directives:

• A directive that opens the expression is no longer written on the declaration line. The line ends at => and the directive starts the next line, which avoids CS1040.
• A directive after the last line of code moves the semicolon. The last line of code may sit in one branch of an #if, so terminating it would leave the other branches unterminated. When any directive follows that line, the ; goes on a line of its own after the last directive, where every branch reaches it. This avoids #endif; (CS1025) and leaves no branch without a terminator.
• When code follows the last directive, that code is terminated as before. Comment-only lines are still skipped, as An expression body whose last line ends in a // comment gets its semicolon inside the comment: public int P => x // note; does not compile (CS1002) #144 introduced.

The repro now renders:

int P =>
#if DEBUG
1
#else
2
#endif
;

The issue's example form, with the ; inside each branch, was one option it offered. A trailing ; after the directives is correct whether the branches are complete expressions or fragments of one, such as 1 #if DEBUG + 2 #endif. Terminating inside each branch would break that second case.

Tests

• New tests cover the repro through ExpressionBodyFactory and through AccessorKind.Expression, plus an expression that ends in a conditional after code on the arrow line.
• A regression guard covers code after the last directive, which still gets its own ;.
• With the fix reverted, the three directive tests fail.
• The full suite passes: 253 tests on net10.0. The library builds with no warnings on every target framework.
• This branch merges cleanly with Refuse a line break in a doc comment cref or name before writing [patch] #160 and Brace a member body that holds only comments or directives [patch] #161.

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Generated by Claude Code

[matt-edmondson]

I merged main into this branch to resolve the conflict with #161, which also added helpers to TemplateRendering.cs. Both sides' helpers are kept, and HasCode now reuses IsCode.

This PR's CI will show 6 failures that aren't caused by this PR. They are the six ScopesTests.PragmaScopeRejectsWarningsThatSpanLinesBeforeWriting data rows, and they fail on main too, at 08f896f.

• Cause: Skip empty entries in a PragmaScope warning list [patch] #167 trims each entry in the IEnumerable<string> PragmaScope constructor (warning.Trim()). That strips the trailing terminator from "CS1591\n", which is the input Refuse an empty #if condition and a multi-line directive argument [patch] #155's test expects to be rejected. The two PRs' changes conflict in meaning even though they merged without a text conflict.
• Possible fix, to go in its own PR rather than this one: reject a line terminator in any entry before trimming. For example, in JoinWarnings, throw ArgumentException when LineTerminators.Contains(warning) before the Trim(). The other option is to trim only spaces and tabs.

Every other test passes on the merged branch: 285 of 291.

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Generated by Claude Code

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

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