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[Async Refactoring] Add parens around custom error cast #38583

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Merged
merged 1 commit into from
Jul 23, 2021
Merged

[Async Refactoring] Add parens around custom error cast #38583

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40 changes: 27 additions & 13 deletions lib/IDE/Refactoring.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -7596,17 +7596,32 @@ class AsyncConverter : private SourceEntityWalker {
OS << tok::r_paren;
}

/// If the error type of \p HandlerDesc is more specialized than \c Error,
/// adds an 'as! CustomError' cast to the more specialized error type to the
/// output stream.
void
addCastToCustomErrorTypeIfNecessary(const AsyncHandlerDesc &HandlerDesc) {
const ASTContext &Ctx = HandlerDesc.getHandler()->getASTContext();
/// Adds a forwarded error argument to a completion handler call. If the error
/// type of \p HandlerDesc is more specialized than \c Error, an
/// 'as! CustomError' cast to the more specialized error type will be added to
/// the output stream.
void addForwardedErrorArgument(StringRef ErrorName,
const AsyncHandlerDesc &HandlerDesc) {
// If the error type is already Error, we can pass it as-is.
auto ErrorType = *HandlerDesc.getErrorType();
if (ErrorType->getCanonicalType() != Ctx.getExceptionType()) {
OS << " " << tok::kw_as << tok::exclaim_postfix << " ";
ErrorType->lookThroughSingleOptionalType()->print(OS);
if (ErrorType->getCanonicalType() == getASTContext().getExceptionType()) {
OS << ErrorName;
return;
}

// Otherwise we need to add a force cast to the destination custom error
// type. If this is for an Error? parameter, we'll need to add parens around
// the cast to silence a compiler warning about force casting never
// producing nil.
auto RequiresParens = HandlerDesc.getErrorParam().hasValue();
if (RequiresParens)
OS << tok::l_paren;

OS << ErrorName << " " << tok::kw_as << tok::exclaim_postfix << " ";
ErrorType->lookThroughSingleOptionalType()->print(OS);

if (RequiresParens)
OS << tok::r_paren;
}

/// If \p T has a natural default value like \c nil for \c Optional or \c ()
Expand Down Expand Up @@ -7637,8 +7652,7 @@ class AsyncConverter : private SourceEntityWalker {
if (HandlerDesc.HasError && Index == HandlerDesc.params().size() - 1) {
// The error parameter is the last argument of the completion handler.
if (ResultName.empty()) {
OS << "error";
addCastToCustomErrorTypeIfNecessary(HandlerDesc);
addForwardedErrorArgument("error", HandlerDesc);
} else {
addDefaultValueOrPlaceholder(HandlerDesc.params()[Index].getPlainType());
}
Expand Down Expand Up @@ -7707,8 +7721,8 @@ class AsyncConverter : private SourceEntityWalker {
OS << tok::period_prefix << "success" << tok::l_paren << ResultName
<< tok::r_paren;
} else {
OS << tok::period_prefix << "failure" << tok::l_paren << "error";
addCastToCustomErrorTypeIfNecessary(HandlerDesc);
OS << tok::period_prefix << "failure" << tok::l_paren;
addForwardedErrorArgument("error", HandlerDesc);
OS << tok::r_paren;
}
break;
Expand Down
4 changes: 2 additions & 2 deletions test/refactoring/ConvertAsync/basic.swift
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Expand Up @@ -133,7 +133,7 @@ func customError(completion: (String?, CustomError?) -> Void) { }
// ASYNC-CUSTOMERROR-NEXT: let result = try await customError()
// ASYNC-CUSTOMERROR-NEXT: completion(result, nil)
// ASYNC-CUSTOMERROR-NEXT: } catch {
// ASYNC-CUSTOMERROR-NEXT: completion(nil, error as! CustomError)
// ASYNC-CUSTOMERROR-NEXT: completion(nil, (error as! CustomError))
// ASYNC-CUSTOMERROR-NEXT: }
// ASYNC-CUSTOMERROR-NEXT: }
// ASYNC-CUSTOMERROR-NEXT: }
Expand Down Expand Up @@ -308,7 +308,7 @@ func genericError<E>(completion: (String?, E?) -> Void) where E: Error { }
// GENERIC-ERROR-NEXT: let result: String = try await genericError()
// GENERIC-ERROR-NEXT: completion(result, nil)
// GENERIC-ERROR-NEXT: } catch {
// GENERIC-ERROR-NEXT: completion(nil, error as! E)
// GENERIC-ERROR-NEXT: completion(nil, (error as! E))
// GENERIC-ERROR-NEXT: }
// GENERIC-ERROR-NEXT: }
// GENERIC-ERROR-NEXT: }
Expand Down
2 changes: 1 addition & 1 deletion test/refactoring/ConvertAsync/variable_as_callback.swift
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Expand Up @@ -317,7 +317,7 @@ func testGenericErrorVariableCompletionHandler<MyGenericError>(completionHandler
// GENERIC-ERROR-NEXT: let result: String = try await genericError()
// GENERIC-ERROR-NEXT: completionHandler(result, nil)
// GENERIC-ERROR-NEXT: } catch {
// GENERIC-ERROR-NEXT: completionHandler(nil, error as! MyGenericError)
// GENERIC-ERROR-NEXT: completionHandler(nil, (error as! MyGenericError))
// GENERIC-ERROR-NEXT: }

// RUN: %refactor-check-compiles -convert-to-async -dump-text -source-filename %s -pos=%(line+2):1 | %FileCheck -check-prefix=DEFAULT-ARGS-FUNC %s
Expand Down