sbenza added inline comments.
================
Comment at: unittests/ASTMatchers/ASTMatchersTest.cpp:4994
@@ +4993,3 @@
+ EXPECT_TRUE(matches("typedef int hasUnderlyingTypeTest;",
+ typedefDecl(hasUnderlyingType(asString("int")))));
+ EXPECT_TRUE(matches("typedef const int T;",
----------------
aaron.ballman wrote:
> LegalizeAdulthood wrote:
> > aaron.ballman wrote:
> > > LegalizeAdulthood wrote:
> > > > aaron.ballman wrote:
> > > > > Thank you for those examples! Given the following code:
> > > > > ```
> > > > > typedef int foo;
> > > > > typedef foo bar;
> > > > >
> > > > > bar i;
> > > > > ```
> > > > > clang-query> match varDecl(hasType(asString("int")))
> > > > > 0 matches.
> > > > > clang-query> match varDecl(hasType(asString("foo")))
> > > > > 0 matches.
> > > > > clang-query> match varDecl(hasType(asString("bar")))
> > > > >
> > > > > Match #1:
> > > > >
> > > > > E:\Desktop\t.cpp:4:1: note: "root" binds here
> > > > > bar i;
> > > > > ^~~~~
> > > > > 1 match.
> > > > >
> > > > > So hasType() looks at what the immediate type is for the declaration
> > > > > (which we document, yay us!). Based on that, I don't think
> > > > > hasUnderlyingType() makes sense -- you should modify hasType() to
> > > > > work on a TypedefNameDecl (not just a TypedefDecl!) so that it looks
> > > > > at the immediate type of the type definition. I would expect your
> > > > > tests then to result in:
> > > > > ```
> > > > > 1: typedef void (fn)(void);
> > > > > 2: typedef fn foo;
> > > > > 3: typedef int bar;
> > > > > 4: typedef int (f);
> > > > > 5: typedef int (fn2)(int);
> > > > > clang-query> match typedefDecl(hasType(asString("int")))
> > > > >
> > > > > Match #1:
> > > > >
> > > > > /tmp/a.cpp:3:1: note: "root" binds here
> > > > > typedef int bar;
> > > > > ^~~~~~~~~~~~~~~
> > > > >
> > > > > Match #2:
> > > > >
> > > > > /tmp/a.cpp:4:1: note: "root" binds here
> > > > > typedef int (f);
> > > > > ^~~~~~~~~~~~~~~
> > > > > 2 matches.
> > > > > clang-query> match typedefDecl(hasType(typedefType()))
> > > > >
> > > > > Match #1:
> > > > >
> > > > > /tmp/a.cpp:2:1: note: "root" binds here
> > > > > typedef fn foo;
> > > > > ^~~~~~~~~~~~~~
> > > > > 1 match.
> > > > > clang-query> match typedefDecl(hasType(parenType()))
> > > > >
> > > > > Match #1:
> > > > >
> > > > > /tmp/a.cpp:1:1: note: "root" binds here
> > > > > typedef void (fn)(void);
> > > > > ^~~~~~~~~~~~~~~~~~~~~~~
> > > > >
> > > > > Match #2:
> > > > >
> > > > > /tmp/a.cpp:4:1: note: "root" binds here
> > > > > typedef int (f);
> > > > > ^~~~~~~~~~~~~~~
> > > > >
> > > > > Match #3:
> > > > >
> > > > > /tmp/a.cpp:5:1: note: "root" binds here
> > > > > typedef int (fn2)(int);
> > > > > ^~~~~~~~~~~~~~~~~~~~~~
> > > > > 3 matches.
> > > > > clang-query> match
> > > > > typedefDecl(hasType(parenType(innerType(functionType()))))
> > > > >
> > > > > Match #1:
> > > > >
> > > > > /tmp/a.cpp:1:1: note: "root" binds here
> > > > > typedef void (fn)(void);
> > > > > ^~~~~~~~~~~~~~~~~~~~~~~
> > > > >
> > > > > Match #2:
> > > > >
> > > > > /tmp/a.cpp:5:1: note: "root" binds here
> > > > > typedef int (fn2)(int);
> > > > > ^~~~~~~~~~~~~~~~~~~~~~
> > > > > 2 matches.
> > > > > ```
> > > > > The end results are the same, so this is just changing the way the
> > > > > information is surfaced to the user that is logically consistent.
> > > > > ValueDecls have an immediate type, and so do TypedefDecls. By using
> > > > > TypedefNameDecl instead of TypedefDecl, this also covers the case
> > > > > where hasType() is useful for an alias-declaration. (We don't expose
> > > > > the matcher for that yet, but it seems quite reasonable to add in the
> > > > > future, and it would be nice for hasType to automatically work with
> > > > > that.)
> > > > >
> > > > > You can implement this with a helper function to handle abstracting
> > > > > away the call to getType() vs getUnderlyingType(), then updating the
> > > > > hasType() matchers to use it. Something like:
> > > > > ```
> > > > > template <typename Ty>
> > > > > struct UnderlyingTypeGetter {
> > > > > static QualType get(const Ty &Node) {
> > > > > return Node.getType();
> > > > > }
> > > > > };
> > > > >
> > > > > template <>
> > > > > QualType UnderlyingTypeGetter<TypedefNameDecl>::get(const
> > > > > TypedefNameDecl &Node) {
> > > > > return Node.getUnderlyingType();
> > > > > }
> > > > > ```
> > > > > (Somewhere in ASTMatchersInternal.h most likely.)
> > > > >
> > > > When I try to extend `hasType` to work on `TypedefDecl`, I get this
> > > > error:
> > > >
> > > > ```
> > > > error: static assertion failed: right polymorphic conversion
> > > > static_assert(TypeListContainsSuperOf<ReturnTypes, T>::value,
> > > > ```
> > > >
> > > > ...because `TypedefDecl` is derived from `NamedDecl` and the existing
> > > > definition for `hasType` looks like this:
> > > >
> > > > ```
> > > > AST_POLYMORPHIC_MATCHER_P_OVERLOAD(hasType,
> > > > AST_POLYMORPHIC_SUPPORTED_TYPES(Expr,
> > > >
> > > > ValueDecl),
> > > > internal::Matcher<Decl>,
> > > > InnerMatcher, 1) {
> > > > return qualType(hasDeclaration(InnerMatcher))
> > > > .matches(Node.getType(), Finder, Builder);
> > > > }
> > > > ```
> > > >
> > > > So I'll need some guidance on how to extend `hasType` to work for
> > > > `TypedefNamedDecl` nodes. I don't understand exactly what all these
> > > > nasty macros do. So far, I've simply made changes by imitation, but my
> > > > approach didn't work this time.
> > > This ({F1302460}) does all of what you need (sans documentation, testing,
> > > etc).
> > >
> > > (File should be attached, but if you need me to send it to you via email,
> > > I can do so -- I've never tried this with Phab before.)
> > What you had was very similar to what I attempted. You wrote:
> >
> > ```AST_POLYMORPHIC_SUPPORTED_TYPES(Expr, TypdefNameDecl, ValueDecl)```
> >
> > and I wrote
> >
> > ```AST_POLYMORPHIC_SUPPORTED_TYPES(Expr, ValueDecl, TypedefNameDecl)```
> >
> > so apparently the derivation relations between the arguments to this macro
> > are order dependent?
> I was being OCD and alphabetizing, but I think you may be right that order
> matters. @sbenza, may know more (if it's purposeful, we should document it).
Order should not matter.
We just iterate over the list to see if there is a matching type.
I could not reproduce the compiler error.
http://reviews.llvm.org/D8149
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