Improve the fix-its for -Wparentheses to ensure that the fix-it

suggestions follow recovery. Additionally, add a note to these
diagnostics which suggests a fix-it for changing the behavior to what
the user probably meant. Examples:

t.cpp:2:9: warning: & has lower precedence than ==; == will be evaluated first
      [-Wparentheses]
  if (i & j == k) {
        ^~~~~~~~
          (     )
t.cpp:2:9: note: place parentheses around the & expression to evaluate it first
  if (i & j == k) {
        ^
      (    )

t.cpp:14:9: warning: using the result of an assignment as a condition
without
      parentheses [-Wparentheses]
  if (i = f()) {
      ~~^~~~~
      (      )
t.cpp:14:9: note: use '==' to turn this assignment into an equality
comparison
  if (i = f()) {
        ^
        ==

llvm-svn: 92975

1 files changed, 26 insertions, 2 deletions

diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 216e2e60980..f1311098336 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -6150,8 +6150,9 @@ Action::OwningExprResult Sema::CreateBuiltinBinOp(SourceLocation OpLoc,
 /// ParenRange in parentheses.
 static void SuggestParentheses(Sema &Self, SourceLocation Loc,
                                const PartialDiagnostic &PD,
-                               SourceRange ParenRange)
-{
+                               SourceRange ParenRange,
+                      const PartialDiagnostic &SecondPD = PartialDiagnostic(0),
+                               SourceRange SecondParenRange = SourceRange()) {
   SourceLocation EndLoc = Self.PP.getLocForEndOfToken(ParenRange.getEnd());
   if (!ParenRange.getEnd().isFileID() || EndLoc.isInvalid()) {
     // We can't display the parentheses, so just dig the
@@ -6163,6 +6164,21 @@ static void SuggestParentheses(Sema &Self, SourceLocation Loc,
   Self.Diag(Loc, PD)
     << CodeModificationHint::CreateInsertion(ParenRange.getBegin(), "(")
     << CodeModificationHint::CreateInsertion(EndLoc, ")");
+  
+  if (!SecondPD.getDiagID())
+    return;
+  
+  EndLoc = Self.PP.getLocForEndOfToken(SecondParenRange.getEnd());
+  if (!SecondParenRange.getEnd().isFileID() || EndLoc.isInvalid()) {
+    // We can't display the parentheses, so just dig the
+    // warning/error and return.
+    Self.Diag(Loc, SecondPD);
+    return;
+  }
+  
+  Self.Diag(Loc, SecondPD)
+    << CodeModificationHint::CreateInsertion(SecondParenRange.getBegin(), "(")
+    << CodeModificationHint::CreateInsertion(EndLoc, ")");
 }
 
 /// DiagnoseBitwisePrecedence - Emit a warning when bitwise and comparison
@@ -6194,12 +6210,18 @@ static void DiagnoseBitwisePrecedence(Sema &Self, BinaryOperator::Opcode Opc,
       PDiag(diag::warn_precedence_bitwise_rel)
           << SourceRange(lhs->getLocStart(), OpLoc)
           << BinOp::getOpcodeStr(Opc) << BinOp::getOpcodeStr(lhsopc),
+      lhs->getSourceRange(),
+      PDiag(diag::note_precedence_bitwise_first)
+          << BinOp::getOpcodeStr(Opc),
       SourceRange(cast<BinOp>(lhs)->getRHS()->getLocStart(), rhs->getLocEnd()));
   else if (BinOp::isComparisonOp(rhsopc))
     SuggestParentheses(Self, OpLoc,
       PDiag(diag::warn_precedence_bitwise_rel)
           << SourceRange(OpLoc, rhs->getLocEnd())
           << BinOp::getOpcodeStr(Opc) << BinOp::getOpcodeStr(rhsopc),
+      rhs->getSourceRange(),
+      PDiag(diag::note_precedence_bitwise_first)
+        << BinOp::getOpcodeStr(Opc),
       SourceRange(lhs->getLocEnd(), cast<BinOp>(rhs)->getLHS()->getLocStart()));
 }
 
@@ -7251,6 +7273,8 @@ void Sema::DiagnoseAssignmentAsCondition(Expr *E) {
     << E->getSourceRange()
     << CodeModificationHint::CreateInsertion(Open, "(")
     << CodeModificationHint::CreateInsertion(Close, ")");
+  Diag(Loc, diag::note_condition_assign_to_comparison)
+    << CodeModificationHint::CreateReplacement(Loc, "==");
 }
 
 bool Sema::CheckBooleanCondition(Expr *&E, SourceLocation Loc) {