Introduce then statements
#67454
Introduce then statements
#67454
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hamishknight
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hamishknight
requested review from
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ahoppen,
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| // Issue a warning when the expression is on a different line than | ||
| // the 'then' keyword, but both have the same indentation. | ||
| if (SourceMgr.getLineAndColumnInBuffer(thenLoc).second == | ||
| SourceMgr.getLineAndColumnInBuffer(exprLoc).second) { | ||
| diagnose(exprLoc, diag::unindented_code_after_then); | ||
| diagnose(exprLoc, diag::indent_expression_to_silence); | ||
| } |
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Hmm. Would be nice if we could do the same in swift-syntax but there currently isn’t any way to emit warnings from the parser (only from the lexer).
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Depending on where we land with the newline rule, we may not even need this logic in the first place
hamishknight
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@hamishknight I am doing something similar that is going to need to be gated by an experimental feature in SwiftSyntax. Is it possible for you to split out the addition of the experimental feature support into a separate commit in this same PR. This will make it easier for people to cargo cult this work forward by just looking at a small commit that implements this rather than the large commit here. (I am not just doing this for myself, I am thinking down the line about other people). |
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Or actually from talking @ahoppen this is going to take some time for you to do. I am going to see if I can cargo cult some of your work around the experimental feature since I need the same thing for reference bindings. |
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@gottesmm Hey Michael, I already did this :) See #67826 + swiftlang/swift-syntax#2041. There's one more commit on the swift-syntax side that's needed to enable testing of experimental features (swiftlang/swift-syntax@b0414b1), I can land that separately if needed. |
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@hamishknight can you land it separately in that case? My work is almost ready to go |
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Sure thing: swiftlang/swift-syntax#2051 |
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@swift-ci please build toolchain |
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| let x = if .random() { | ||
| print("hello") | ||
| then 0 | ||
| // expected-error@-1 {{cannot find 'then' in scope}} |
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Should this be diagnosed as a disabled feature instead if then here otherwise would be valid?
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This is a source breaking change, so we can't generally diagnose it as a disabled feature, we could apply a heuristic to generate that diagnostic, but I'm not convinced it's worth it.
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Maybe it's not worth it if we are going to enable this by default soon, but it would be great for user experience to hint that all they need is to enable a flag in situations when it's syntactically unambiguous that they meant then statement.
These allow multi-statement `if`/`switch` expression branches that can produce a value at the end by saying `then <expr>`. This is gated behind `-enable-experimental-feature ThenStatements` pending evolution discussion.
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@swift-ci please test |
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@swift-ci please build toolchain |
These allow multi-statement
if/switchexpression branches that can produce a value at the end by sayingthen <expr>. This is gated behind-enable-experimental-feature ThenStatementspending evolution discussion.