Implement -Wenum-compare, which warns when comparing two enums of

different types. We omit the warning when the enum types are anonymous.
Unlike GCC, this warning does not distinguish between C++ and C/ObjC for
controling whether it is on by default, it is always on by default.

Original patch contributed by Richard Trieu (@ Google), I fixed some
style issues, and cleaned it up for submission.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@125739 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index b815426f6c49054a61a126431fe004e61e469f24..985a771028c7b5480fc6bafaf35e5824fea1e937 100644 (file)
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -2514,6 +2514,9 @@ def warn_lunsigned_always_true_comparison : Warning<
 def warn_runsigned_always_true_comparison : Warning<
   "comparison of %0 unsigned%select{| enum}2 expression is always %1">,
   InGroup<TautologicalCompare>;
+def warn_comparison_of_mixed_enum_types : Warning<
+  "comparison of two values with different enumeration types (%0 and %1)">,
+  InGroup<DiagGroup<"enum-compare">>;
 
 def err_invalid_this_use : Error<
   "invalid use of 'this' outside of a nonstatic member function">;

diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index 94dd27d0c221afe6274734ed1ab77e431af181fa..052dd4b956fe00e45f3cac28cb7b4d1cd2ea8273 100644 (file)
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -6637,6 +6637,24 @@ QualType Sema::CheckCompareOperands(Expr *&lex, Expr *&rex, SourceLocation Loc,
   QualType lType = lex->getType();
   QualType rType = rex->getType();
 
+  Expr *LHSStripped = lex->IgnoreParenImpCasts();
+  Expr *RHSStripped = rex->IgnoreParenImpCasts();
+  QualType LHSStrippedType = LHSStripped->getType();
+  QualType RHSStrippedType = RHSStripped->getType();
+
+  // Two different enums will raise a warning when compared.
+  if (const EnumType *LHSEnumType = LHSStrippedType->getAs<EnumType>()) {
+    if (const EnumType *RHSEnumType = RHSStrippedType->getAs<EnumType>()) {
+      if (LHSEnumType->getDecl()->getIdentifier() &&
+          RHSEnumType->getDecl()->getIdentifier() &&
+          !Context.hasSameUnqualifiedType(LHSStrippedType, RHSStrippedType)) {
+        Diag(Loc, diag::warn_comparison_of_mixed_enum_types)
+          << LHSStrippedType << RHSStrippedType
+          << lex->getSourceRange() << rex->getSourceRange();
+      }
+    }
+  }
+
   if (!lType->hasFloatingRepresentation() &&
       !(lType->isBlockPointerType() && isRelational) &&
       !lex->getLocStart().isMacroID() &&
@@ -6651,8 +6669,6 @@ QualType Sema::CheckCompareOperands(Expr *&lex, Expr *&rex, SourceLocation Loc,
     // obvious cases in the definition of the template anyways. The idea is to
     // warn when the typed comparison operator will always evaluate to the same
     // result.
-    Expr *LHSStripped = lex->IgnoreParenImpCasts();
-    Expr *RHSStripped = rex->IgnoreParenImpCasts();
     if (DeclRefExpr* DRL = dyn_cast<DeclRefExpr>(LHSStripped)) {
       if (DeclRefExpr* DRR = dyn_cast<DeclRefExpr>(RHSStripped)) {
         if (DRL->getDecl() == DRR->getDecl() &&

diff --git a/test/SemaCXX/overloaded-operator.cpp b/test/SemaCXX/overloaded-operator.cpp
index a9d3f128e2b113d2360c070af93f4cefa3d940e4..4399a026eaf49f34a2d3da886f250c71a52d24e2 100644 (file)
--- a/test/SemaCXX/overloaded-operator.cpp
+++ b/test/SemaCXX/overloaded-operator.cpp
@@ -70,11 +70,11 @@ struct E2 {
 // C++ [over.match.oper]p3 - enum restriction.
 float& operator==(E1, E2); 
 
-void enum_test(Enum1 enum1, Enum2 enum2, E1 e1, E2 e2) {
+void enum_test(Enum1 enum1, Enum2 enum2, E1 e1, E2 e2, Enum1 next_enum1) {
   float &f1 = (e1 == e2);
   float &f2 = (enum1 == e2); 
   float &f3 = (e1 == enum2); 
-  float &f4 = (enum1 == enum2);  // expected-error{{non-const lvalue reference to type 'float' cannot bind to a temporary of type 'bool'}}
+  float &f4 = (enum1 == next_enum1);  // expected-error{{non-const lvalue reference to type 'float' cannot bind to a temporary of type 'bool'}}
 }
 
 // PR5244 - Argument-dependent lookup would include the two operators below,

diff --git a/test/SemaCXX/warn-enum-compare.cpp b/test/SemaCXX/warn-enum-compare.cpp
new file mode 100644 (file)
index 0000000..52639e7
--- /dev/null
+++ b/test/SemaCXX/warn-enum-compare.cpp
@@ -0,0 +1,212 @@
+// RUN: %clang_cc1 %s -fsyntax-only -verify
+
+enum Foo { FooA, FooB, FooC };
+enum Bar { BarD, BarE, BarF };
+enum { AnonAA = 42, AnonAB = 43 };
+enum { AnonBA = 44, AnonBB = 45 };
+
+namespace name1 {
+  enum Foo {F1, F2, F3};
+  enum Baz {B1, B2, B3};
+}
+
+namespace name2 {
+  enum Baz {B1, B2, B3};
+}
+
+using name1::Baz;
+using name1::B1;
+using name2::B2;
+typedef name1::Foo oneFoo;
+typedef name1::Foo twoFoo;
+Foo getFoo();
+Bar getBar();
+
+void test () {
+  Foo x = FooA;
+  Bar y = BarD;
+  Baz z = name1::B3;
+  name1::Foo a;
+  oneFoo b;
+  twoFoo c;
+
+  while (x == FooA);
+  while (y == BarD);
+  while (a == name1::F1);
+  while (z == name1::B2);
+  while (a == b);
+  while (a == c);
+  while (b == c);
+  while (B1 == name1::B2);
+  while (B2 == name2::B1);
+  while (x == AnonAA);
+  while (AnonBB == y);
+  while (AnonAA == AnonAB);
+  while (AnonAB == AnonBA);
+  while (AnonBB == AnonAA);
+
+  while ((x) == FooA);
+  while ((y) == BarD);
+  while ((a) == name1::F1);
+  while (z == (name1::B2));
+  while (a == (b));
+  while (a == (c));
+  while ((b) == (c));
+  while ((B1) == (name1::B2));
+  while ((B2) == (name2::B1));
+
+  while (((x)) == FooA);
+  while ((y) == (BarD));
+  while ((a) == (name1::F1));
+  while (z == (name1::B2));
+  while ((a) == ((((b)))));
+  while (((a)) == (c));
+  while ((b) == (((c))));
+  while ((((((B1))))) == (((name1::B2))));
+  while (B2 == ((((((name2::B1)))))));
+
+  while (B1 == B2); // expected-warning  {{comparison of two values with different enumeration types ('name1::Baz' and 'name2::Baz')}}
+  while (name1::B2 == name2::B3); // expected-warning  {{comparison of two values with different enumeration types ('name1::Baz' and 'name2::Baz')}}
+  while (z == name2::B2); // expected-warning  {{comparison of two values with different enumeration types ('name1::Baz' and 'name2::Baz')}}
+
+  while (((((B1)))) == B2); // expected-warning  {{comparison of two values with different enumeration types ('name1::Baz' and 'name2::Baz')}}
+  while (name1::B2 == (name2::B3)); // expected-warning  {{comparison of two values with different enumeration types ('name1::Baz' and 'name2::Baz')}}
+  while (z == ((((name2::B2))))); // expected-warning  {{comparison of two values with different enumeration types ('name1::Baz' and 'name2::Baz')}}
+
+  while ((((B1))) == (((B2)))); // expected-warning  {{comparison of two values with different enumeration types ('name1::Baz' and 'name2::Baz')}}
+  while ((name1::B2) == (((name2::B3)))); // expected-warning  {{comparison of two values with different enumeration types ('name1::Baz' and 'name2::Baz')}}
+  while ((((z))) == (name2::B2)); // expected-warning  {{comparison of two values with different enumeration types ('name1::Baz' and 'name2::Baz')}}
+
+  while (x == a); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'name1::Foo')}}
+  while (x == b); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'oneFoo' (aka 'name1::Foo'))}}
+  while (x == c); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'twoFoo' (aka 'name1::Foo'))}}
+
+  while (x == y); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (x != y); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (x >= y); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (x <= y); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (x > y); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (x < y); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+
+  while (FooB == y); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (FooB != y); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (FooB >= y); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (FooB <= y); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (FooB > y); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (FooB < y); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+
+  while (FooB == BarD); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (FooB != BarD); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (FooB >= BarD); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (FooB <= BarD); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (FooB > BarD); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (FooB < BarD); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+
+  while (x == BarD); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (x != BarD); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (x >= BarD); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (x <= BarD); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (x > BarD); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (x < BarD); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+
+  while (getFoo() == y); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (getFoo() != y); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (getFoo() >= y); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (getFoo() <= y); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (getFoo() > y); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (getFoo() < y); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+
+  while (getFoo() == BarD); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (getFoo() != BarD); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (getFoo() >= BarD); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (getFoo() <= BarD); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (getFoo() > BarD); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (getFoo() < BarD); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+
+  while (getFoo() == getBar()); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (getFoo() != getBar()); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (getFoo() >= getBar()); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (getFoo() <= getBar()); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (getFoo() > getBar()); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (getFoo() < getBar()); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+
+  while (FooB == getBar()); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (FooB != getBar()); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (FooB >= getBar()); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (FooB <= getBar()); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (FooB > getBar()); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (FooB < getBar()); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+
+  while (x == getBar()); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (x != getBar()); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (x >= getBar()); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (x <= getBar()); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (x > getBar()); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+  while (x < getBar()); // expected-warning  {{comparison of two values with different enumeration types ('Foo' and 'Bar')}}
+
+
+
+  while (y == x); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (y != x); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (y >= x); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (y <= x); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (y > x); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (y < x); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+
+  while (y == FooB); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (y != FooB); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (y >= FooB); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (y <= FooB); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (y > FooB); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (y < FooB); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+
+  while (BarD == FooB); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (BarD != FooB); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (BarD >= FooB); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (BarD <= FooB); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (BarD > FooB); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (BarD <FooB); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+
+  while (BarD == x); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (BarD != x); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (BarD >= x); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (BarD <= x); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (BarD < x); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (BarD > x); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+
+  while (y == getFoo()); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (y != getFoo()); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (y >= getFoo()); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (y <= getFoo()); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (y > getFoo()); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (y < getFoo()); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+
+  while (BarD == getFoo()); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (BarD != getFoo()); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (BarD >= getFoo()); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (BarD <= getFoo()); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (BarD > getFoo()); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (BarD < getFoo()); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+
+  while (getBar() == getFoo()); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (getBar() != getFoo()); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (getBar() >= getFoo()); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (getBar() <= getFoo()); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (getBar() > getFoo()); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (getBar() < getFoo()); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+
+  while (getBar() == FooB); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (getBar() != FooB); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (getBar() >= FooB); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (getBar() <= FooB); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (getBar() > FooB); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (getBar() < FooB); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+
+  while (getBar() == x); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (getBar() != x); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (getBar() >= x); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (getBar() <= x); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (getBar() > x); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+  while (getBar() < x); // expected-warning  {{comparison of two values with different enumeration types ('Bar' and 'Foo')}}
+
+}