[clang-tidy] Improving narrowing conversions

Summary:
Newly flagged narrowing conversions:
 - integer to narrower signed integer (this is compiler implementation defined),
 - integer - floating point narrowing conversions,
 - floating point - integer narrowing conversions,
 - constants with narrowing conversions (even in ternary operator).

Reviewers: hokein, alexfh, aaron.ballman, JonasToth

Reviewed By: aaron.ballman, JonasToth

Subscribers: lebedev.ri, courbet, nemanjai, xazax.hun, kbarton, cfe-commits

Tags: #clang-tools-extra

Differential Revision: https://reviews.llvm.org/D53488

git-svn-id: https://llvm.org/svn/llvm-project/clang-tools-extra/trunk@347570 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 476 insertions, 33 deletions

diff --git a/clang-tidy/cppcoreguidelines/NarrowingConversionsCheck.cpp b/clang-tidy/cppcoreguidelines/NarrowingConversionsCheck.cpp
index 3a22c1e9..132d84ad 100644
--- a/clang-tidy/cppcoreguidelines/NarrowingConversionsCheck.cpp
+++ b/clang-tidy/cppcoreguidelines/NarrowingConversionsCheck.cpp
@@ -9,7 +9,13 @@
 
 #include "NarrowingConversionsCheck.h"
 #include "clang/AST/ASTContext.h"
+#include "clang/AST/Type.h"
 #include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "llvm/ADT/APSInt.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/SmallVector.h"
+
+#include <cstdint>
 
 using namespace clang::ast_matchers;
 
@@ -17,52 +23,423 @@ namespace clang {
 namespace tidy {
 namespace cppcoreguidelines {
 
-// FIXME: Check double -> float truncation. Pay attention to casts:
+NarrowingConversionsCheck::NarrowingConversionsCheck(StringRef Name,
+                                                     ClangTidyContext *Context)
+    : ClangTidyCheck(Name, Context),
+      WarnOnFloatingPointNarrowingConversion(
+          Options.get("WarnOnFloatingPointNarrowingConversion", 1)),
+      PedanticMode(Options.get("PedanticMode", 0)) {}
+
 void NarrowingConversionsCheck::registerMatchers(MatchFinder *Finder) {
   // ceil() and floor() are guaranteed to return integers, even though the type
   // is not integral.
-  const auto IsCeilFloorCall = callExpr(callee(functionDecl(
-      hasAnyName("::ceil", "::std::ceil", "::floor", "::std::floor"))));
-
-  const auto IsFloatExpr =
-      expr(hasType(realFloatingPointType()), unless(IsCeilFloorCall));
+  const auto IsCeilFloorCallExpr = expr(callExpr(callee(functionDecl(
+      hasAnyName("::ceil", "::std::ceil", "::floor", "::std::floor")))));
 
-  // casts:
+  // Casts:
   //   i = 0.5;
   //   void f(int); f(0.5);
-  Finder->addMatcher(implicitCastExpr(hasImplicitDestinationType(isInteger()),
-                                      hasSourceExpression(IsFloatExpr),
-                                      unless(hasParent(castExpr())),
-                                      unless(isInTemplateInstantiation()))
-                         .bind("cast"),
-                     this);
+  Finder->addMatcher(
+      implicitCastExpr(hasImplicitDestinationType(builtinType()),
+                       hasSourceExpression(hasType(builtinType())),
+                       unless(hasSourceExpression(IsCeilFloorCallExpr)),
+                       unless(hasParent(castExpr())),
+                       unless(isInTemplateInstantiation()))
+          .bind("cast"),
+      this);
 
   // Binary operators:
   //   i += 0.5;
-  Finder->addMatcher(
-      binaryOperator(isAssignmentOperator(),
-                     // The `=` case generates an implicit cast which is covered
-                     // by the previous matcher.
-                     unless(hasOperatorName("=")),
-                     hasLHS(hasType(isInteger())), hasRHS(IsFloatExpr),
-                     unless(isInTemplateInstantiation()))
-          .bind("op"),
-      this);
+  Finder->addMatcher(binaryOperator(isAssignmentOperator(),
+                                    hasLHS(expr(hasType(builtinType()))),
+                                    hasRHS(expr(hasType(builtinType()))),
+                                    unless(hasRHS(IsCeilFloorCallExpr)),
+                                    unless(isInTemplateInstantiation()),
+                                    // The `=` case generates an implicit cast
+                                    // which is covered by the previous matcher.
+                                    unless(hasOperatorName("=")))
+                         .bind("binary_op"),
+                     this);
 }
 
-void NarrowingConversionsCheck::check(const MatchFinder::MatchResult &Result) {
-  if (const auto *Op = Result.Nodes.getNodeAs<BinaryOperator>("op")) {
-    if (Op->getBeginLoc().isMacroID())
+static const BuiltinType *getBuiltinType(const Expr &E) {
+  return E.getType().getCanonicalType().getTypePtr()->getAs<BuiltinType>();
+}
+
+static QualType getUnqualifiedType(const Expr &E) {
+  return E.getType().getUnqualifiedType();
+}
+
+static APValue getConstantExprValue(const ASTContext &Ctx, const Expr &E) {
+  llvm::APSInt IntegerConstant;
+  if (E.isIntegerConstantExpr(IntegerConstant, Ctx))
+    return APValue(IntegerConstant);
+  APValue Constant;
+  if (Ctx.getLangOpts().CPlusPlus && E.isCXX11ConstantExpr(Ctx, &Constant))
+    return Constant;
+  return {};
+}
+
+static bool getIntegerConstantExprValue(const ASTContext &Context,
+                                        const Expr &E, llvm::APSInt &Value) {
+  APValue Constant = getConstantExprValue(Context, E);
+  if (!Constant.isInt())
+    return false;
+  Value = Constant.getInt();
+  return true;
+}
+
+static bool getFloatingConstantExprValue(const ASTContext &Context,
+                                         const Expr &E, llvm::APFloat &Value) {
+  APValue Constant = getConstantExprValue(Context, E);
+  if (!Constant.isFloat())
+    return false;
+  Value = Constant.getFloat();
+  return true;
+}
+
+namespace {
+
+struct IntegerRange {
+  bool Contains(const IntegerRange &From) const {
+    return llvm::APSInt::compareValues(Lower, From.Lower) <= 0 &&
+           llvm::APSInt::compareValues(Upper, From.Upper) >= 0;
+  }
+
+  bool Contains(const llvm::APSInt &Value) const {
+    return llvm::APSInt::compareValues(Lower, Value) <= 0 &&
+           llvm::APSInt::compareValues(Upper, Value) >= 0;
+  }
+
+  llvm::APSInt Lower;
+  llvm::APSInt Upper;
+};
+
+} // namespace
+
+static IntegerRange createFromType(const ASTContext &Context,
+                                   const BuiltinType &T) {
+  if (T.isFloatingPoint()) {
+    unsigned PrecisionBits = llvm::APFloatBase::semanticsPrecision(
+        Context.getFloatTypeSemantics(T.desugar()));
+    // Contrary to two's complement integer, floating point values are
+    // symmetric and have the same number of positive and negative values.
+    // The range of valid integers for a floating point value is:
+    // [-2^PrecisionBits, 2^PrecisionBits]
+
+    // Values are created with PrecisionBits plus two bits:
+    // - One to express the missing negative value of 2's complement
+    //   representation.
+    // - One for the sign.
+    llvm::APSInt UpperValue(PrecisionBits + 2, /*isUnsigned*/ false);
+    UpperValue.setBit(PrecisionBits);
+    llvm::APSInt LowerValue(PrecisionBits + 2, /*isUnsigned*/ false);
+    LowerValue.setBit(PrecisionBits);
+    LowerValue.setSignBit();
+    return {LowerValue, UpperValue};
+  }
+  assert(T.isInteger() && "Unexpected builtin type");
+  uint64_t TypeSize = Context.getTypeSize(&T);
+  bool IsUnsignedInteger = T.isUnsignedInteger();
+  return {llvm::APSInt::getMinValue(TypeSize, IsUnsignedInteger),
+          llvm::APSInt::getMaxValue(TypeSize, IsUnsignedInteger)};
+}
+
+static bool isWideEnoughToHold(const ASTContext &Context,
+                               const BuiltinType &FromType,
+                               const BuiltinType &ToType) {
+  IntegerRange FromIntegerRange = createFromType(Context, FromType);
+  IntegerRange ToIntegerRange = createFromType(Context, ToType);
+  return ToIntegerRange.Contains(FromIntegerRange);
+}
+
+static bool isWideEnoughToHold(const ASTContext &Context,
+                               const llvm::APSInt &IntegerConstant,
+                               const BuiltinType &ToType) {
+  IntegerRange ToIntegerRange = createFromType(Context, ToType);
+  return ToIntegerRange.Contains(IntegerConstant);
+}
+
+static llvm::SmallString<64> getValueAsString(const llvm::APSInt &Value,
+                                              uint64_t HexBits) {
+  llvm::SmallString<64> Str;
+  Value.toString(Str, 10);
+  if (HexBits > 0) {
+    Str.append(" (0x");
+    llvm::SmallString<32> HexValue;
+    Value.toStringUnsigned(HexValue, 16);
+    for (size_t I = HexValue.size(); I < (HexBits / 4); ++I)
+      Str.append("0");
+    Str.append(HexValue);
+    Str.append(")");
+  }
+  return Str;
+}
+
+void NarrowingConversionsCheck::diagNarrowType(SourceLocation SourceLoc,
+                                               const Expr &Lhs,
+                                               const Expr &Rhs) {
+  diag(SourceLoc, "narrowing conversion from %0 to %1")
+      << getUnqualifiedType(Rhs) << getUnqualifiedType(Lhs);
+}
+
+void NarrowingConversionsCheck::diagNarrowTypeToSignedInt(
+    SourceLocation SourceLoc, const Expr &Lhs, const Expr &Rhs) {
+  diag(SourceLoc, "narrowing conversion from %0 to signed type %1 is "
+                  "implementation-defined")
+      << getUnqualifiedType(Rhs) << getUnqualifiedType(Lhs);
+}
+
+void NarrowingConversionsCheck::diagNarrowIntegerConstant(
+    SourceLocation SourceLoc, const Expr &Lhs, const Expr &Rhs,
+    const llvm::APSInt &Value) {
+  diag(SourceLoc,
+       "narrowing conversion from constant value %0 of type %1 to %2")
+      << getValueAsString(Value, /*NoHex*/ 0) << getUnqualifiedType(Rhs)
+      << getUnqualifiedType(Lhs);
+}
+
+void NarrowingConversionsCheck::diagNarrowIntegerConstantToSignedInt(
+    SourceLocation SourceLoc, const Expr &Lhs, const Expr &Rhs,
+    const llvm::APSInt &Value, const uint64_t HexBits) {
+  diag(SourceLoc, "narrowing conversion from constant value %0 of type %1 "
+                  "to signed type %2 is implementation-defined")
+      << getValueAsString(Value, HexBits) << getUnqualifiedType(Rhs)
+      << getUnqualifiedType(Lhs);
+}
+
+void NarrowingConversionsCheck::diagNarrowConstant(SourceLocation SourceLoc,
+                                                   const Expr &Lhs,
+                                                   const Expr &Rhs) {
+  diag(SourceLoc, "narrowing conversion from constant %0 to %1")
+      << getUnqualifiedType(Rhs) << getUnqualifiedType(Lhs);
+}
+
+void NarrowingConversionsCheck::diagConstantCast(SourceLocation SourceLoc,
+                                                 const Expr &Lhs,
+                                                 const Expr &Rhs) {
+  diag(SourceLoc, "constant value should be of type of type %0 instead of %1")
+      << getUnqualifiedType(Lhs) << getUnqualifiedType(Rhs);
+}
+
+void NarrowingConversionsCheck::diagNarrowTypeOrConstant(
+    const ASTContext &Context, SourceLocation SourceLoc, const Expr &Lhs,
+    const Expr &Rhs) {
+  APValue Constant = getConstantExprValue(Context, Rhs);
+  if (Constant.isInt())
+    return diagNarrowIntegerConstant(SourceLoc, Lhs, Rhs, Constant.getInt());
+  if (Constant.isFloat())
+    return diagNarrowConstant(SourceLoc, Lhs, Rhs);
+  return diagNarrowType(SourceLoc, Lhs, Rhs);
+}
+
+void NarrowingConversionsCheck::handleIntegralCast(const ASTContext &Context,
+                                                   SourceLocation SourceLoc,
+                                                   const Expr &Lhs,
+                                                   const Expr &Rhs) {
+  const BuiltinType *ToType = getBuiltinType(Lhs);
+  // From [conv.integral]p7.3.8:
+  // Conversions to unsigned integer is well defined so no warning is issued.
+  // "The resulting value is the smallest unsigned value equal to the source
+  // value modulo 2^n where n is the number of bits used to represent the
+  // destination type."
+  if (ToType->isUnsignedInteger())
+    return;
+  const BuiltinType *FromType = getBuiltinType(Rhs);
+  llvm::APSInt IntegerConstant;
+  if (getIntegerConstantExprValue(Context, Rhs, IntegerConstant)) {
+    if (!isWideEnoughToHold(Context, IntegerConstant, *ToType))
+      diagNarrowIntegerConstantToSignedInt(SourceLoc, Lhs, Rhs, IntegerConstant,
+                                           Context.getTypeSize(FromType));
+    return;
+  }
+  if (!isWideEnoughToHold(Context, *FromType, *ToType))
+    diagNarrowTypeToSignedInt(SourceLoc, Lhs, Rhs);
+}
+
+void NarrowingConversionsCheck::handleIntegralToBoolean(
+    const ASTContext &Context, SourceLocation SourceLoc, const Expr &Lhs,
+    const Expr &Rhs) {
+  // Conversion from Integral to Bool value is well defined.
+
+  // We keep this function (even if it is empty) to make sure that
+  // handleImplicitCast and handleBinaryOperator are symmetric in their behavior
+  // and handle the same cases.
+}
+
+void NarrowingConversionsCheck::handleIntegralToFloating(
+    const ASTContext &Context, SourceLocation SourceLoc, const Expr &Lhs,
+    const Expr &Rhs) {
+  const BuiltinType *ToType = getBuiltinType(Lhs);
+  llvm::APSInt IntegerConstant;
+  if (getIntegerConstantExprValue(Context, Rhs, IntegerConstant)) {
+    if (!isWideEnoughToHold(Context, IntegerConstant, *ToType))
+      diagNarrowIntegerConstant(SourceLoc, Lhs, Rhs, IntegerConstant);
+    return;
+  }
+  const BuiltinType *FromType = getBuiltinType(Rhs);
+  if (!isWideEnoughToHold(Context, *FromType, *ToType))
+    diagNarrowType(SourceLoc, Lhs, Rhs);
+}
+
+void NarrowingConversionsCheck::handleFloatingToIntegral(
+    const ASTContext &Context, SourceLocation SourceLoc, const Expr &Lhs,
+    const Expr &Rhs) {
+  llvm::APFloat FloatConstant(0.0);
+
+  // We always warn when Rhs is non-constexpr.
+  if (!getFloatingConstantExprValue(Context, Rhs, FloatConstant))
+    return diagNarrowType(SourceLoc, Lhs, Rhs);
+
+  QualType DestType = Lhs.getType();
+  unsigned DestWidth = Context.getIntWidth(DestType);
+  bool DestSigned = DestType->isSignedIntegerOrEnumerationType();
+  llvm::APSInt Result = llvm::APSInt(DestWidth, !DestSigned);
+  bool IsExact = false;
+  bool Overflows = FloatConstant.convertToInteger(
+                       Result, llvm::APFloat::rmTowardZero, &IsExact) &
+                   llvm::APFloat::opInvalidOp;
+  // We warn iff the constant floating point value is not exactly representable.
+  if (Overflows || !IsExact)
+    return diagNarrowConstant(SourceLoc, Lhs, Rhs);
+
+  if (PedanticMode)
+    return diagConstantCast(SourceLoc, Lhs, Rhs);
+}
+
+void NarrowingConversionsCheck::handleFloatingToBoolean(
+    const ASTContext &Context, SourceLocation SourceLoc, const Expr &Lhs,
+    const Expr &Rhs) {
+  return diagNarrowTypeOrConstant(Context, SourceLoc, Lhs, Rhs);
+}
+
+void NarrowingConversionsCheck::handleBooleanToSignedIntegral(
+    const ASTContext &Context, SourceLocation SourceLoc, const Expr &Lhs,
+    const Expr &Rhs) {
+  // Conversion from Bool to SignedIntegral value is well defined.
+
+  // We keep this function (even if it is empty) to make sure that
+  // handleImplicitCast and handleBinaryOperator are symmetric in their behavior
+  // and handle the same cases.
+}
+
+void NarrowingConversionsCheck::handleFloatingCast(const ASTContext &Context,
+                                                   SourceLocation SourceLoc,
+                                                   const Expr &Lhs,
+                                                   const Expr &Rhs) {
+  if (WarnOnFloatingPointNarrowingConversion) {
+    const BuiltinType *ToType = getBuiltinType(Lhs);
+    APValue Constant = getConstantExprValue(Context, Rhs);
+    if (Constant.isFloat()) {
+      // From [dcl.init.list]p7.2:
+      // Floating point constant narrowing only takes place when the value is
+      // not within destination range. We convert the value to the destination
+      // type and check if the resulting value is infinity.
+      llvm::APFloat Tmp = Constant.getFloat();
+      bool UnusedLosesInfo;
+      Tmp.convert(Context.getFloatTypeSemantics(ToType->desugar()),
+                  llvm::APFloatBase::rmNearestTiesToEven, &UnusedLosesInfo);
+      if (Tmp.isInfinity())
+        diagNarrowConstant(SourceLoc, Lhs, Rhs);
       return;
-    diag(Op->getOperatorLoc(), "narrowing conversion from %0 to %1")
-        << Op->getRHS()->getType() << Op->getLHS()->getType();
+    }
+    const BuiltinType *FromType = getBuiltinType(Rhs);
+    if (ToType->getKind() < FromType->getKind())
+      diagNarrowType(SourceLoc, Lhs, Rhs);
+  }
+}
+
+void NarrowingConversionsCheck::handleBinaryOperator(const ASTContext &Context,
+                                                     SourceLocation SourceLoc,
+                                                     const Expr &Lhs,
+                                                     const Expr &Rhs) {
+  assert(!Lhs.isInstantiationDependent() && !Rhs.isInstantiationDependent() &&
+         "Dependent types must be check before calling this function");
+  const BuiltinType *LhsType = getBuiltinType(Lhs);
+  const BuiltinType *RhsType = getBuiltinType(Rhs);
+  if (RhsType == nullptr || LhsType == nullptr)
     return;
+  if (RhsType->getKind() == BuiltinType::Bool && LhsType->isSignedInteger())
+    return handleBooleanToSignedIntegral(Context, SourceLoc, Lhs, Rhs);
+  if (RhsType->isInteger() && LhsType->getKind() == BuiltinType::Bool)
+    return handleIntegralToBoolean(Context, SourceLoc, Lhs, Rhs);
+  if (RhsType->isInteger() && LhsType->isFloatingPoint())
+    return handleIntegralToFloating(Context, SourceLoc, Lhs, Rhs);
+  if (RhsType->isInteger() && LhsType->isInteger())
+    return handleIntegralCast(Context, SourceLoc, Lhs, Rhs);
+  if (RhsType->isFloatingPoint() && LhsType->getKind() == BuiltinType::Bool)
+    return handleFloatingToBoolean(Context, SourceLoc, Lhs, Rhs);
+  if (RhsType->isFloatingPoint() && LhsType->isInteger())
+    return handleFloatingToIntegral(Context, SourceLoc, Lhs, Rhs);
+  if (RhsType->isFloatingPoint() && LhsType->isFloatingPoint())
+    return handleFloatingCast(Context, SourceLoc, Lhs, Rhs);
+}
+
+bool NarrowingConversionsCheck::handleConditionalOperator(
+    const ASTContext &Context, const Expr &Lhs, const Expr &Rhs) {
+  if (const auto *CO = llvm::dyn_cast<ConditionalOperator>(&Rhs)) {
+    // We have an expression like so: `output = cond ? lhs : rhs`
+    // From the point of view of narrowing conversion we treat it as two
+    // expressions `output = lhs` and `output = rhs`.
+    handleBinaryOperator(Context, CO->getLHS()->getExprLoc(), Lhs,
+                         *CO->getLHS());
+    handleBinaryOperator(Context, CO->getRHS()->getExprLoc(), Lhs,
+                         *CO->getRHS());
+    return true;
   }
-  const auto *Cast = Result.Nodes.getNodeAs<ImplicitCastExpr>("cast");
-  if (Cast->getBeginLoc().isMacroID())
+  return false;
+}
+
+void NarrowingConversionsCheck::handleImplicitCast(
+    const ASTContext &Context, const ImplicitCastExpr &Cast) {
+  if (Cast.getExprLoc().isMacroID())
     return;
-  diag(Cast->getExprLoc(), "narrowing conversion from %0 to %1")
-      << Cast->getSubExpr()->getType() << Cast->getType();
+  const Expr &Lhs = Cast;
+  const Expr &Rhs = *Cast.getSubExpr();
+  if (Lhs.isInstantiationDependent() || Rhs.isInstantiationDependent())
+    return;
+  if (handleConditionalOperator(Context, Lhs, Rhs))
+    return;
+  SourceLocation SourceLoc = Lhs.getExprLoc();
+  switch (Cast.getCastKind()) {
+  case CK_BooleanToSignedIntegral:
+    return handleBooleanToSignedIntegral(Context, SourceLoc, Lhs, Rhs);
+  case CK_IntegralToBoolean:
+    return handleIntegralToBoolean(Context, SourceLoc, Lhs, Rhs);
+  case CK_IntegralToFloating:
+    return handleIntegralToFloating(Context, SourceLoc, Lhs, Rhs);
+  case CK_IntegralCast:
+    return handleIntegralCast(Context, SourceLoc, Lhs, Rhs);
+  case CK_FloatingToBoolean:
+    return handleFloatingToBoolean(Context, SourceLoc, Lhs, Rhs);
+  case CK_FloatingToIntegral:
+    return handleFloatingToIntegral(Context, SourceLoc, Lhs, Rhs);
+  case CK_FloatingCast:
+    return handleFloatingCast(Context, SourceLoc, Lhs, Rhs);
+  default:
+    break;
+  }
+}
+
+void NarrowingConversionsCheck::handleBinaryOperator(const ASTContext &Context,
+                                                     const BinaryOperator &Op) {
+  if (Op.getBeginLoc().isMacroID())
+    return;
+  const Expr &Lhs = *Op.getLHS();
+  const Expr &Rhs = *Op.getRHS();
+  if (Lhs.isInstantiationDependent() || Rhs.isInstantiationDependent())
+    return;
+  if (handleConditionalOperator(Context, Lhs, Rhs))
+    return;
+  handleBinaryOperator(Context, Rhs.getBeginLoc(), Lhs, Rhs);
+}
+
+void NarrowingConversionsCheck::check(const MatchFinder::MatchResult &Result) {
+  if (const auto *Op = Result.Nodes.getNodeAs<BinaryOperator>("binary_op"))
+    return handleBinaryOperator(*Result.Context, *Op);
+  if (const auto *Cast = Result.Nodes.getNodeAs<ImplicitCastExpr>("cast"))
+    return handleImplicitCast(*Result.Context, *Cast);
+  llvm_unreachable("must be binary operator or cast expression");
 }
 
 } // namespace cppcoreguidelines
diff --git a/clang-tidy/cppcoreguidelines/NarrowingConversionsCheck.h b/clang-tidy/cppcoreguidelines/NarrowingConversionsCheck.h
index 35f58bc2..3e72248f 100644
--- a/clang-tidy/cppcoreguidelines/NarrowingConversionsCheck.h
+++ b/clang-tidy/cppcoreguidelines/NarrowingConversionsCheck.h
@@ -24,10 +24,76 @@ namespace cppcoreguidelines {
 /// http://clang.llvm.org/extra/clang-tidy/checks/cppcoreguidelines-narrowing-conversions.html
 class NarrowingConversionsCheck : public ClangTidyCheck {
 public:
-  NarrowingConversionsCheck(StringRef Name, ClangTidyContext *Context)
-      : ClangTidyCheck(Name, Context) {}
+  NarrowingConversionsCheck(StringRef Name, ClangTidyContext *Context);
+
   void registerMatchers(ast_matchers::MatchFinder *Finder) override;
   void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+
+private:
+  void diagNarrowType(SourceLocation SourceLoc, const Expr &Lhs,
+                      const Expr &Rhs);
+
+  void diagNarrowTypeToSignedInt(SourceLocation SourceLoc, const Expr &Lhs,
+                                 const Expr &Rhs);
+
+  void diagNarrowIntegerConstant(SourceLocation SourceLoc, const Expr &Lhs,
+                                 const Expr &Rhs, const llvm::APSInt &Value);
+
+  void diagNarrowIntegerConstantToSignedInt(SourceLocation SourceLoc,
+                                            const Expr &Lhs, const Expr &Rhs,
+                                            const llvm::APSInt &Value,
+                                            const uint64_t HexBits);
+
+  void diagNarrowConstant(SourceLocation SourceLoc, const Expr &Lhs,
+                          const Expr &Rhs);
+
+  void diagConstantCast(SourceLocation SourceLoc, const Expr &Lhs,
+                        const Expr &Rhs);
+
+  void diagNarrowTypeOrConstant(const ASTContext &Context,
+                                SourceLocation SourceLoc, const Expr &Lhs,
+                                const Expr &Rhs);
+
+  void handleIntegralCast(const ASTContext &Context, SourceLocation SourceLoc,
+                          const Expr &Lhs, const Expr &Rhs);
+
+  void handleIntegralToBoolean(const ASTContext &Context,
+                               SourceLocation SourceLoc, const Expr &Lhs,
+                               const Expr &Rhs);
+
+  void handleIntegralToFloating(const ASTContext &Context,
+                                SourceLocation SourceLoc, const Expr &Lhs,
+                                const Expr &Rhs);
+
+  void handleFloatingToIntegral(const ASTContext &Context,
+                                SourceLocation SourceLoc, const Expr &Lhs,
+                                const Expr &Rhs);
+
+  void handleFloatingToBoolean(const ASTContext &Context,
+                               SourceLocation SourceLoc, const Expr &Lhs,
+                               const Expr &Rhs);
+
+  void handleBooleanToSignedIntegral(const ASTContext &Context,
+                                     SourceLocation SourceLoc, const Expr &Lhs,
+                                     const Expr &Rhs);
+
+  void handleFloatingCast(const ASTContext &Context, SourceLocation SourceLoc,
+                          const Expr &Lhs, const Expr &Rhs);
+
+  void handleBinaryOperator(const ASTContext &Context, SourceLocation SourceLoc,
+                            const Expr &Lhs, const Expr &Rhs);
+
+  bool handleConditionalOperator(const ASTContext &Context, const Expr &Lhs,
+                                 const Expr &Rhs);
+
+  void handleImplicitCast(const ASTContext &Context,
+                          const ImplicitCastExpr &Cast);
+
+  void handleBinaryOperator(const ASTContext &Context,
+                            const BinaryOperator &Op);
+
+  const bool WarnOnFloatingPointNarrowingConversion;
+  const bool PedanticMode;
 };
 
 } // namespace cppcoreguidelines