diff options
| -rw-r--r-- | clang/include/clang/Basic/DiagnosticKinds.def | 3 | ||||
| -rw-r--r-- | clang/lib/Sema/SemaExpr.cpp | 24 | ||||
| -rw-r--r-- | clang/test/Sema/exprs.c | 9 |
3 files changed, 34 insertions, 2 deletions
diff --git a/clang/include/clang/Basic/DiagnosticKinds.def b/clang/include/clang/Basic/DiagnosticKinds.def index d7eee9f1a68..3e06932b224 100644 --- a/clang/include/clang/Basic/DiagnosticKinds.def +++ b/clang/include/clang/Basic/DiagnosticKinds.def @@ -1045,6 +1045,9 @@ DIAG(err_union_as_base_class, ERROR, DIAG(err_incomplete_base_class, ERROR, "base class has incomplete type") +DIAG(warn_not_compound_assign, WARNING, + "use of unary operator that may be intended as compound assignment (%0=)") + // CHECK: printf format string errors DIAG(warn_printf_not_string_constant, WARNING, "format string is not a string literal (potentially insecure)") diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp index 2bb3983acf8..c7db342ae4f 100644 --- a/clang/lib/Sema/SemaExpr.cpp +++ b/clang/lib/Sema/SemaExpr.cpp @@ -1901,10 +1901,30 @@ inline QualType Sema::CheckAssignmentOperands( // C99 6.5.16.1 } AssignConvertType ConvTy; - if (compoundType.isNull()) + if (compoundType.isNull()) { + // Simple assignment "x = y". ConvTy = CheckSingleAssignmentConstraints(lhsType, rex); - else + + // If the RHS is a unary plus or minus, check to see if they = and + are + // right next to each other. If so, the user may have typo'd "x =+ 4" + // instead of "x += 4". + Expr *RHSCheck = rex; + if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(RHSCheck)) + RHSCheck = ICE->getSubExpr(); + if (UnaryOperator *UO = dyn_cast<UnaryOperator>(RHSCheck)) { + if ((UO->getOpcode() == UnaryOperator::Plus || + UO->getOpcode() == UnaryOperator::Minus) && + loc.isFileID() && UO->getOperatorLoc().isFileID() && + // Only if the two operators are exactly adjacent. + loc.getFileLocWithOffset(1) == UO->getOperatorLoc()) + Diag(loc, diag::warn_not_compound_assign, + UO->getOpcode() == UnaryOperator::Plus ? "+" : "-", + SourceRange(UO->getOperatorLoc(), UO->getOperatorLoc())); + } + } else { + // Compound assignment "x += y" ConvTy = CheckCompoundAssignmentConstraints(lhsType, rhsType); + } if (DiagnoseAssignmentResult(ConvTy, loc, lhsType, rhsType, rex, "assigning")) diff --git a/clang/test/Sema/exprs.c b/clang/test/Sema/exprs.c index fc506f7a2b3..c98a7ed0c83 100644 --- a/clang/test/Sema/exprs.c +++ b/clang/test/Sema/exprs.c @@ -15,3 +15,12 @@ void test3() { (__extension__ x) = 10; } +// rdar://6162726 +void test4() { + static int var; + var =+ 5; // expected-warning {{use of unary operator that may be intended as compound assignment (+=)}} + var =- 5; // expected-warning {{use of unary operator that may be intended as compound assignment (-=)}} + var = +5; + var = -5; +} + |
