Hi alexfh,
This changeset extends the simplify boolean expression check in `clang-tidy` to
simplify `if (e) return true; return false;` to `return e;` (note the lack of
an else clause on the if statement.)
http://reviews.llvm.org/D9810
Files:
clang-tidy/readability/SimplifyBooleanExprCheck.cpp
clang-tidy/readability/SimplifyBooleanExprCheck.h
test/clang-tidy/readability-simplify-bool-expr.cpp
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Index: clang-tidy/readability/SimplifyBooleanExprCheck.cpp
===================================================================
--- clang-tidy/readability/SimplifyBooleanExprCheck.cpp
+++ clang-tidy/readability/SimplifyBooleanExprCheck.cpp
@@ -48,6 +48,11 @@
const char IfAssignBoolId[] = "if-assign";
const char IfAssignNotBoolId[] = "if-assign-not";
const char IfAssignObjId[] = "if-assign-obj";
+const char CompoundId[] = "compound";
+const char CompoundIfReturnsBoolId[] = "compound-if";
+const char CompoundReturnId[] = "compound-return";
+const char CompoundBoolId[] = "compound-bool";
+const char CompoundNotBoolId[] = "compound-bool-not";
const char IfStmtId[] = "if";
const char LHSId[] = "lhs-expr";
@@ -57,6 +62,8 @@
"redundant boolean literal supplied to boolean operator";
const char SimplifyConditionDiagnostic[] =
"redundant boolean literal in if statement condition";
+const char SimplifyConditionalReturnDiagnostic[] =
+ "redundant boolean literal in conditional return statement";
const CXXBoolLiteralExpr *getBoolLiteral(const MatchFinder::MatchResult &Result,
StringRef Id) {
@@ -67,9 +74,11 @@
: Literal;
}
-internal::Matcher<Stmt> ReturnsBool(bool Value, StringRef Id = "") {
- auto SimpleReturnsBool = returnStmt(
- has(boolLiteral(equals(Value)).bind(Id.empty() ? "ignored" : Id)));
+internal::Matcher<Stmt> returnsBool(bool Value, StringRef Id = "") {
+ auto SimpleReturnsBool =
+ returnStmt(
+ has(boolLiteral(equals(Value)).bind(Id.empty() ? "ignored" : Id)))
+ .bind("returns-bool");
return anyOf(SimpleReturnsBool,
compoundStmt(statementCountIs(1), has(SimpleReturnsBool)));
}
@@ -108,16 +117,31 @@
StringRef NegatedOperator = negatedOperator(BinOp);
if (!NegatedOperator.empty()) {
return (getText(Result, *BinOp->getLHS()) + " " + NegatedOperator +
- " " + getText(Result, *BinOp->getRHS()))
- .str();
+ " " + getText(Result, *BinOp->getRHS())).str();
}
}
}
StringRef Text = getText(Result, *E);
return (Negated ? (needsParensAfterUnaryNegation(E) ? "!(" + Text + ")"
: "!" + Text)
- : Text)
- .str();
+ : Text).str();
+}
+
+bool isFollowedBy(const CompoundStmt *Compound, const Stmt *Before,
+ const Stmt *After) {
+ if (Compound->size() < 2) {
+ return false;
+ }
+
+ CompoundStmt::const_body_iterator BeforeIt = Compound->body_begin();
+ CompoundStmt::const_body_iterator AfterIt = Compound->body_begin();
+ for (++AfterIt; AfterIt != Compound->body_end(); ++BeforeIt, ++AfterIt) {
+ if (*BeforeIt == Before && *AfterIt == After) {
+ return true;
+ }
+ }
+
+ return false;
}
} // namespace
@@ -200,8 +224,8 @@
void SimplifyBooleanExprCheck::matchIfReturnsBool(MatchFinder *Finder,
bool Value, StringRef Id) {
Finder->addMatcher(ifStmt(isExpansionInMainFile(),
- hasThen(ReturnsBool(Value, ThenLiteralId)),
- hasElse(ReturnsBool(!Value))).bind(Id),
+ hasThen(returnsBool(Value, ThenLiteralId)),
+ hasElse(returnsBool(!Value))).bind(Id),
this);
}
@@ -225,6 +249,20 @@
this);
}
+void SimplifyBooleanExprCheck::matchCompoundIfReturnsBool(MatchFinder *Finder,
+ bool Value,
+ StringRef Id) {
+ Finder->addMatcher(
+ compoundStmt(
+ allOf(hasAnySubstatement(
+ ifStmt(
+ hasThen(returnsBool(Value, CompoundId)),
+ unless(hasElse(stmt()))).bind(CompoundIfReturnsBoolId)),
+ hasAnySubstatement(returnStmt(has(boolLiteral(equals(!Value))))
+ .bind(CompoundReturnId)))).bind(Id),
+ this);
+}
+
void SimplifyBooleanExprCheck::registerMatchers(MatchFinder *Finder) {
matchBoolBinOpExpr(Finder, true, "&&", RightExpressionId);
matchBoolBinOpExpr(Finder, false, "||", RightExpressionId);
@@ -257,6 +295,9 @@
matchIfAssignsBool(Finder, true, IfAssignBoolId);
matchIfAssignsBool(Finder, false, IfAssignNotBoolId);
+
+ matchCompoundIfReturnsBool(Finder, true, CompoundBoolId);
+ matchCompoundIfReturnsBool(Finder, false, CompoundNotBoolId);
}
void SimplifyBooleanExprCheck::check(const MatchFinder::MatchResult &Result) {
@@ -296,6 +337,12 @@
} else if (const auto *IfAssignNot =
Result.Nodes.getNodeAs<IfStmt>(IfAssignNotBoolId)) {
replaceWithAssignment(Result, IfAssignNot, true);
+ } else if (const auto *Compound =
+ Result.Nodes.getNodeAs<CompoundStmt>(CompoundBoolId)) {
+ replaceCompoundReturnWithCondition(Result, Compound);
+ } else if (const auto *Compound =
+ Result.Nodes.getNodeAs<CompoundStmt>(CompoundNotBoolId)) {
+ replaceCompoundReturnWithCondition(Result, Compound, true);
}
}
@@ -349,10 +396,28 @@
std::string Replacement = ("return " + Condition + Terminator).str();
SourceLocation Start =
Result.Nodes.getNodeAs<CXXBoolLiteralExpr>(ThenLiteralId)->getLocStart();
- diag(Start, "redundant boolean literal in conditional return statement")
+ diag(Start, SimplifyConditionalReturnDiagnostic)
<< FixItHint::CreateReplacement(If->getSourceRange(), Replacement);
}
+void SimplifyBooleanExprCheck::replaceCompoundReturnWithCondition(
+ const MatchFinder::MatchResult &Result, const CompoundStmt *Compound,
+ bool Negated) {
+ const auto *IfRet = Result.Nodes.getNodeAs<IfStmt>(CompoundIfReturnsBoolId);
+ const auto *Ret = Result.Nodes.getNodeAs<ReturnStmt>(CompoundReturnId);
+
+ if (isFollowedBy(Compound, IfRet, Ret)) {
+ const Expr *Condition = IfRet->getCond();
+ const auto *Lit = Result.Nodes.getNodeAs<CXXBoolLiteralExpr>(CompoundId);
+ assert(Lit);
+ std::string Replacement =
+ "return " + replacementExpression(Result, Negated, Condition);
+ diag(Lit->getLocStart(), SimplifyConditionalReturnDiagnostic)
+ << FixItHint::CreateReplacement(
+ SourceRange(IfRet->getLocStart(), Ret->getLocEnd()), Replacement);
+ }
+}
+
void SimplifyBooleanExprCheck::replaceWithAssignment(
const MatchFinder::MatchResult &Result, const IfStmt *IfAssign,
bool Negated) {
Index: clang-tidy/readability/SimplifyBooleanExprCheck.h
===================================================================
--- clang-tidy/readability/SimplifyBooleanExprCheck.h
+++ clang-tidy/readability/SimplifyBooleanExprCheck.h
@@ -34,6 +34,8 @@
/// `if (e) return false; else return true;` becomes `return !(e);`
/// `if (e) b = true; else b = false;` becomes `b = e;`
/// `if (e) b = false; else b = true;` becomes `b = !(e);`
+/// `if (e) return true; return false;` becomes `return e;`
+/// `if (e) return false; return true;` becomes `return !e;`
///
class SimplifyBooleanExprCheck : public ClangTidyCheck {
public:
@@ -67,6 +69,9 @@
void matchIfAssignsBool(ast_matchers::MatchFinder *Finder, bool Value,
StringRef Id);
+ void matchCompoundIfReturnsBool(ast_matchers::MatchFinder *Finder, bool Value,
+ StringRef Id);
+
void
replaceWithExpression(const ast_matchers::MatchFinder::MatchResult &Result,
const CXXBoolLiteralExpr *BoolLiteral, bool UseLHS,
@@ -92,6 +97,10 @@
void
replaceWithAssignment(const ast_matchers::MatchFinder::MatchResult &Result,
const IfStmt *If, bool Negated = false);
+
+ void replaceCompoundReturnWithCondition(
+ const ast_matchers::MatchFinder::MatchResult &Result,
+ const CompoundStmt *Compound, bool Negated = false);
};
} // namespace readability
Index: test/clang-tidy/readability-simplify-bool-expr.cpp
===================================================================
--- test/clang-tidy/readability-simplify-bool-expr.cpp
+++ test/clang-tidy/readability-simplify-bool-expr.cpp
@@ -541,3 +541,45 @@
} else
f = false;
}
+
+bool simple_if_return_return(int i) {
+ if (i > 10)
+ return true;
+ return false;
+}
+// CHECK-MESSAGES: :[[@LINE-3]]:12: warning: {{.*}} in conditional return
+// CHECK-FIXES: {{^}}bool simple_if_return_return(int i) {{{$}}
+// CHECK-FIXES: {{^ return i > 10;$}}
+// CHECK-FIXES: {{^}}}{{$}}
+
+bool simple_if_return_return_negated(int i) {
+ if (i > 10)
+ return false;
+ return true;
+}
+// CHECK-MESSAGES: :[[@LINE-3]]:12: warning: {{.*}} in conditional return
+// CHECK-FIXES: {{^}}bool simple_if_return_return_negated(int i) {{{$}}
+// CHECK-FIXES: {{^ return i <= 10;$}}
+// CHECK-FIXES: {{^}}}{{$}}
+
+bool complex_if_return_return(int i) {
+ if (i > 10) {
+ return true;
+ }
+ return false;
+}
+// CHECK-MESSAGES: :[[@LINE-4]]:12: warning: {{.*}} in conditional return
+// CHECK-FIXES: {{^}}bool complex_if_return_return(int i) {{{$}}
+// CHECK-FIXES: {{^ return i > 10;$}}
+// CHECK-FIXES: {{^}}}{{$}}
+
+bool complex_if_return_return_negated(int i) {
+ if (i > 10) {
+ return false;
+ }
+ return true;
+}
+// CHECK-MESSAGES: :[[@LINE-4]]:12: warning: {{.*}} in conditional return
+// CHECK-FIXES: {{^}}bool complex_if_return_return_negated(int i) {{{$}}
+// CHECK-FIXES: {{^ return i <= 10;$}}
+// CHECK-FIXES: {{^}}}{{$}}
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