Commit Graph

6 Commits

Author SHA1 Message Date
Richard Smith 5179eb7821 P0136R1, DR1573, DR1645, DR1715, DR1736, DR1903, DR1941, DR1959, DR1991:
Replace inheriting constructors implementation with new approach, voted into
C++ last year as a DR against C++11.

Instead of synthesizing a set of derived class constructors for each inherited
base class constructor, we make the constructors of the base class visible to
constructor lookup in the derived class, using the normal rules for
using-declarations.

For constructors, UsingShadowDecl now has a ConstructorUsingShadowDecl derived
class that tracks the requisite additional information. We create shadow
constructors (not found by name lookup) in the derived class to model the
actual initialization, and have a new expression node,
CXXInheritedCtorInitExpr, to model the initialization of a base class from such
a constructor. (This initialization is special because it performs real perfect
forwarding of arguments.)

In cases where argument forwarding is not possible (for inalloca calls,
variadic calls, and calls with callee parameter cleanup), the shadow inheriting
constructor is not emitted and instead we directly emit the initialization code
into the caller of the inherited constructor.

Note that this new model is not perfectly compatible with the old model in some
corner cases. In particular:
 * if B inherits a private constructor from A, and C uses that constructor to
   construct a B, then we previously required that A befriends B and B
   befriends C, but the new rules require A to befriend C directly, and
 * if a derived class has its own constructors (and so its implicit default
   constructor is suppressed), it may still inherit a default constructor from
   a base class

llvm-svn: 274049
2016-06-28 19:03:57 +00:00
Serge Pavlov f80df57d39 Update error message text.
Previously if an enumeration was used in a nested name specifier in pre-C++11
language dialect, error message was 'XXX is not a class, namespace, or scoped
enumeration'. This patch removes the word 'scoped' as in C++11 any enumeration
may be used in this context.

llvm-svn: 226410
2015-01-18 19:05:48 +00:00
David Blaikie 6cab596218 Improve diagnostic for using non-class/namespace/scoped enum in a nested name specifier.
Rather than simply saying "X is not a class or namespace", clarify what
X is by providing the aka type in the case where X is a type, or
pointing to the named declaration if there's an unambiguous one to refer
to. In the ambiguous case, the ambiguities are already enumerated
(though could be clarified by describing what kind of entities they are)

Included a few FIXMEs in tests where some further improvements could be
made.

llvm-svn: 201038
2014-02-09 06:54:23 +00:00
Richard Smith b2bfad2355 Remove FIXMEs: these are covered by a core issue which we don't yet implement
(but we happen to get this part right).

llvm-svn: 177958
2013-03-26 01:17:18 +00:00
Richard Smith 7447af48b1 Implement special-case name lookup for inheriting constructors: member
using-declarations with names which look constructor-like are interpreted as
constructor names.

llvm-svn: 177957
2013-03-26 01:15:19 +00:00
Douglas Gregor 9de54ea41b Reimplement constructor declarator parsing to cope with template-ids
that name constructors, the endless joys of out-of-line constructor
definitions, and various other corner cases that the previous hack
never imagined. Fixes PR5688 and tightens up semantic analysis for
constructor names.

Additionally, fixed a problem where we wouldn't properly enter the
declarator scope of a parenthesized declarator. We were entering the
scope, then leaving it when we saw the ")"; now, we re-enter the
declarator scope before parsing the parameter list.

Note that we are forced to perform some tentative parsing within a
class (call it C) to tell the difference between

  C(int); // constructor

and

  C (f)(int); // member function

which is rather unfortunate. And, although it isn't necessary for
correctness, we use the same tentative-parsing mechanism for
out-of-line constructors to improve diagnostics in icky cases like:

  C::C C::f(int); // error: C::C refers to the constructor name, but
                  // we complain nicely and recover by treating it as
                  // a type.

llvm-svn: 93322
2010-01-13 17:31:36 +00:00