When we parse a tag specifier, keep track of whether that tag
specifier resulted in the creation of a new TagDecl node, which
happens either when the tag specifier was a definition or when the tag
specifier was the first declaration of that tag type. This information
has several uses, the first of which is implemented in this commit:
1) In C++, one is not allowed to define tag types within a type
specifier (e.g., static_cast<struct S { int x; } *>(0) is
ill-formed) or within the result or parameter types of a
function. We now diagnose this.
2) We can extend DeclGroups to contain information about any tags
that are declared/defined within the declaration specifiers of a
variable, e.g.,
struct Point { int x, y, z; } p;
This will help improve AST printing and template instantiation,
among other things.
3) For C99, we can keep track of whether a tag type is defined
within the type of a parameter, to properly cope with cases like,
e.g.,
int bar(struct T2 { int x; } y) {
struct T2 z;
}
We can also do similar things wherever there is a type specifier,
e.g., to keep track of where the definition of S occurs in this
legal C99 code:
(struct S { int x, y; } *)0
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@72555 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index 7b36b13..6a2e309 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -2835,8 +2835,16 @@
if (getLangOptions().CPlusPlus)
CheckExtraCXXDefaultArguments(D);
- QualType parmDeclType = GetTypeForDeclarator(D, S);
+ TagDecl *OwnedDecl = 0;
+ QualType parmDeclType = GetTypeForDeclarator(D, S, /*Skip=*/0, &OwnedDecl);
+ if (getLangOptions().CPlusPlus && OwnedDecl && OwnedDecl->isDefinition()) {
+ // C++ [dcl.fct]p6:
+ // Types shall not be defined in return or parameter types.
+ Diag(OwnedDecl->getLocation(), diag::err_type_defined_in_param_type)
+ << Context.getTypeDeclType(OwnedDecl);
+ }
+
// TODO: CHECK FOR CONFLICTS, multiple decls with same name in one scope.
// Can this happen for params? We already checked that they don't conflict
// among each other. Here they can only shadow globals, which is ok.
@@ -3316,11 +3324,13 @@
Sema::DeclPtrTy Sema::ActOnTag(Scope *S, unsigned TagSpec, TagKind TK,
SourceLocation KWLoc, const CXXScopeSpec &SS,
IdentifierInfo *Name, SourceLocation NameLoc,
- AttributeList *Attr, AccessSpecifier AS) {
+ AttributeList *Attr, AccessSpecifier AS,
+ bool &OwnedDecl) {
// If this is not a definition, it must have a name.
assert((Name != 0 || TK == TK_Definition) &&
"Nameless record must be a definition!");
+ OwnedDecl = false;
TagDecl::TagKind Kind;
switch (TagSpec) {
default: assert(0 && "Unknown tag type!");
@@ -3645,6 +3655,7 @@
CurContext->addDecl(Context, New);
}
+ OwnedDecl = true;
return DeclPtrTy::make(New);
}