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[SILGenPattern] Silence redundant unreachable enum case warning (#33336)

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This commit is contained in:
Suyash Srijan
2020-08-22 01:58:44 +01:00
committed by GitHub
parent 83b2ebe8f1
commit 6a7b38d7ef
2 changed files with 32 additions and 8 deletions
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23
lib/SILGen/SILGenPattern.cpp
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@@ -1038,20 +1038,35 @@ void PatternMatchEmission::emitDispatch(ClauseMatrix &clauses, ArgArray args,
SGF.eraseBasicBlock(contBB);
return;
}
// Otherwise, if there is no fallthrough, then the next row is
// unreachable: emit a dead code diagnostic.
// unreachable: emit a dead code diagnostic if:
// 1) It's for a 'default' case (since Space Engine already handles
// unreachable enum case patterns) or it's for a enum case which
// has expression patterns since redundancy checking for such
// patterns isn't sufficiently done by the Space Engine.
// 2) It's for a case statement in a do-catch.
if (!clauses[firstRow].hasFallthroughTo()) {
SourceLoc Loc;
bool isDefault = false;
bool isParentDoCatch = false;
bool caseHasExprPattern = false;
if (auto *S = clauses[firstRow].getClientData<Stmt>()) {
Loc = S->getStartLoc();
if (auto *CS = dyn_cast<CaseStmt>(S))
if (auto *CS = dyn_cast<CaseStmt>(S)) {
caseHasExprPattern = llvm::any_of(
CS->getCaseLabelItems(), [&](const CaseLabelItem item) {
return item.getPattern()->getKind() == PatternKind::Expr;
});
isParentDoCatch = CS->getParentKind() == CaseParentKind::DoCatch;
isDefault = CS->isDefault();
}
} else {
Loc = clauses[firstRow].getCasePattern()->getStartLoc();
}
SGF.SGM.diagnose(Loc, diag::unreachable_case, isDefault);
if (isParentDoCatch || isDefault || caseHasExprPattern) {
SGF.SGM.diagnose(Loc, diag::unreachable_case, isDefault);
}
}
}
}