diff options
| -rw-r--r-- | include/clang/Basic/DiagnosticSemaKinds.td | 3 | ||||
| -rw-r--r-- | lib/Sema/SemaStmt.cpp | 17 | ||||
| -rw-r--r-- | test/Sema/unused-expr.c | 6 |
3 files changed, 26 insertions, 0 deletions
diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td index b66d6cc6e5..ebd3a4e252 100644 --- a/include/clang/Basic/DiagnosticSemaKinds.td +++ b/include/clang/Basic/DiagnosticSemaKinds.td @@ -2359,6 +2359,9 @@ def ext_typecheck_expression_not_constant_but_accepted : Extension< InGroup<GNU>; def warn_unused_expr : Warning<"expression result unused">, InGroup<UnusedValue>; +def warn_unused_voidptr : Warning< + "expression result unused; should this cast be to 'void'?">, + InGroup<UnusedValue>; def warn_unused_property_expr : Warning< "property access result unused - getters should not have side effects">, InGroup<UnusedValue>; diff --git a/lib/Sema/SemaStmt.cpp b/lib/Sema/SemaStmt.cpp index 791de8c2b9..0c55cf5c5c 100644 --- a/lib/Sema/SemaStmt.cpp +++ b/lib/Sema/SemaStmt.cpp @@ -20,6 +20,7 @@ #include "clang/AST/ExprObjC.h" #include "clang/AST/StmtObjC.h" #include "clang/AST/StmtCXX.h" +#include "clang/AST/TypeLoc.h" #include "clang/Lex/Preprocessor.h" #include "clang/Basic/TargetInfo.h" #include "llvm/ADT/STLExtras.h" @@ -126,6 +127,22 @@ void Sema::DiagnoseUnusedExprResult(const Stmt *S) { return; } } + + // Diagnose "(void*) blah" as a typo for "(void) blah". + else if (const CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(E)) { + TypeSourceInfo *TI = CE->getTypeInfoAsWritten(); + QualType T = TI->getType(); + + // We really do want to use the non-canonical type here. + if (T == Context.VoidPtrTy) { + PointerTypeLoc TL = cast<PointerTypeLoc>(TI->getTypeLoc()); + + Diag(Loc, diag::warn_unused_voidptr) + << FixItHint::CreateRemoval(TL.getStarLoc()); + return; + } + } + Diag(Loc, DiagID) << R1 << R2; } diff --git a/test/Sema/unused-expr.c b/test/Sema/unused-expr.c index 4c6c47b345..4ae0d4b465 100644 --- a/test/Sema/unused-expr.c +++ b/test/Sema/unused-expr.c @@ -104,3 +104,9 @@ void t8() { } void t9() __attribute__((warn_unused_result)); // expected-warning {{attribute 'warn_unused_result' cannot be applied to functions without return value}} + +// rdar://7410924 +void *some_function(void); +void t10() { + (void*) some_function(); //expected-warning {{expression result unused; should this cast be to 'void'?}} +} |