On Wed, 2018-11-21 at 13:41 -0500, Jason Merrill wrote:
> On 11/21/18 8:35 AM, David Malcolm wrote:
> > Consider this test case:
> >
> > namespace json
> > {
> > enum { JSON_OBJECT };
> > }
> >
> > void test ()
> > {
> > JSON_OBJECT;
> > }
> >
> > which erroneously accesses an enum value in another namespace
> > without
> > qualifying the access.
> >
> > GCC 6 through 8 issue a suggestion that doesn't mention the
> > namespace:
> >
> > <source>: In function 'void test()':
> > <source>:8:3: error: 'JSON_OBJECT' was not declared in this scope
> > JSON_OBJECT;
> > ^~~~~~~~~~~
> > <source>:8:3: note: suggested alternative:
> > <source>:3:10: note: 'JSON_OBJECT'
> > enum { JSON_OBJECT };
> > ^~~~~~~~~~~
> >
> > which is suboptimal.
> >
> > I made the problem worse with r265610, as gcc 9 now consolidates
> > the single suggestion into the error, and emits:
> >
> > <source>: In function 'void test()':
> > <source>:8:3: error: 'JSON_OBJECT' was not declared in this scope;
> > did
> > you mean 'JSON_OBJECT'?
> > 8 | JSON_OBJECT;
> > | ^~~~~~~~~~~
> > | JSON_OBJECT
> > <source>:3:10: note: 'JSON_OBJECT' declared here
> > 3 | enum { JSON_OBJECT };
> > | ^~~~~~~~~~~
> >
> > where the message:
> > 'JSON_OBJECT' was not declared in this scope; did you mean
> > 'JSON_OBJECT'?
> > is nonsensical.
> >
> > The root cause is that dump_scope doesn't print anything when
> > called for
> > CONST_DECL in a namespace: the scope is an ENUMERAL_TYPE, rather
> > than
> > a namespace.
>
> Although that's only true for unscoped enums.
>
> > This patch tweaks dump_scope to detect ENUMERAL_TYPE, and to use
> > the
> > enclosing namespace, so that the CONST_DECL is dumped as
> > "json::JSON_OBJECT".
> > @@ -182,6 +182,12 @@ dump_scope (cxx_pretty_printer *pp, tree
> > scope, int flags)
> > if (scope == NULL_TREE)
> > return;
> >
> > + /* Enum values will be CONST_DECL with an ENUMERAL_TYPE as their
> > + "scope". Use CP_TYPE_CONTEXT of the ENUMERAL_TYPE, so as to
> > + print the enclosing namespace. */
> > + if (TREE_CODE (scope) == ENUMERAL_TYPE)
> > + scope = CP_TYPE_CONTEXT (scope);
>
> This needs to handle scoped enums differently.
I attempted to trigger this code path (printing a *value* within a
scoped enum via %qE, I believe), but wasn't able to), so I extended
the, ahem, scope of the patch a little, so that when scanning
namespaces for exact matches for a name, we also scan inside scoped
enums, to cover the case where someone doesn't supply the scope.
Hence with the updated patch given e.g.:
enum class vegetable { CARROT, TURNIP };
we're able to offer e.g.:
suggestions-scoped-enums.C:50:3: error: 'CARROT' was not declared in
this scope; did you mean 'vegetable::CARROT'?
50 | CARROT;
| ^~~~~~
| vegetable::CARROT
and this exercises the code path above. The patch updates dump_scope
for scoped enums so that we print the scope when printing the
value ("vegetable::CARROT"), rather than just the name of the value
("CARROT").
> > diff --git a/gcc/testsuite/g++.dg/lookup/suggestions-scoped-enums.C
> > b/gcc/testsuite/g++.dg/lookup/suggestions-scoped-enums.C
> > new file mode 100644
> > index 0000000..2bf3ed6
> > --- /dev/null
> > +++ b/gcc/testsuite/g++.dg/lookup/suggestions-scoped-enums.C
> > @@ -0,0 +1,13 @@
> > +// { dg-do compile { target c++11 } }
> > +// { dg-options "-fdiagnostics-show-caret" }
> > +
> > +enum class vegetable { CARROT, TURNIP };
> > +
> > +void misspelled_value_in_scoped_enum ()
> > +{
> > + vegetable::TURNUP; // { dg-error "'TURNUP' is not a member of
> > 'vegetable'" }
> > + /* { dg-begin-multiline-output "" }
> > + vegetable::TURNUP;
> > + ^~~~~~
> > + { dg-end-multiline-output "" } */
> > +}
>
> I don't see any suggestion in the expected output, and would hope for
> it
> to suggest vegetable::TURNIP.
The updated patch also adds spell-corrections within a scoped enum,
giving:
suggestions-scoped-enums.C:18:14: error: 'TURNUP' is not a member of
'vegetable'; did you mean 'TURNIP'?
18 | vegetable::TURNUP;
| ^~~~~~
| TURNIP
As before, the patch fixes the bogus suggestion in PR c++/88121.
Successfully bootstrapped & regrtested on x86_64-pc-linux-gnu.
OK for trunk?
gcc/cp/ChangeLog:
PR c++/88121
* cp-name-hint.h (suggest_alternative_in_scoped_enum): New decl.
* error.c (dump_scope): Ensure that we print any scope for values
of unscoped enums. Print the scope of values of scoped enums.
(qualified_name_lookup_error): Offer suggestions for failures
within scoped enums by calling suggest_alternative_in_scoped_enum.
* name-lookup.c (class namespace_hints): Update comment to mention
scoped enums.
(namespace_hints::namespace_hints): Call
maybe_add_candidate_for_scoped_enum.
(namespace_hints::maybe_add_candidate_for_scoped_enum): New member
(suggest_alternatives_for): Update comment to mention scoped
enums.
(suggest_alternative_in_scoped_enum): New function.
gcc/testsuite/ChangeLog:
PR c++/88121
* g++.dg/lookup/suggestions-scoped-enums.C: New test.
* g++.dg/lookup/suggestions-unscoped-enums.C: New test.
---
gcc/cp/cp-name-hint.h | 1 +
gcc/cp/error.c | 25 ++++-
gcc/cp/name-lookup.c | 72 ++++++++++++--
.../g++.dg/lookup/suggestions-scoped-enums.C | 110 +++++++++++++++++++++
.../g++.dg/lookup/suggestions-unscoped-enums.C | 91 +++++++++++++++++
5 files changed, 287 insertions(+), 12 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/lookup/suggestions-scoped-enums.C
create mode 100644 gcc/testsuite/g++.dg/lookup/suggestions-unscoped-enums.C
diff --git a/gcc/cp/cp-name-hint.h b/gcc/cp/cp-name-hint.h
index 5d1cdc3..2f9da73 100644
--- a/gcc/cp/cp-name-hint.h
+++ b/gcc/cp/cp-name-hint.h
@@ -33,5 +33,6 @@ along with GCC; see the file COPYING3. If not see
extern name_hint suggest_alternatives_for (location_t, tree, bool);
extern name_hint suggest_alternatives_in_other_namespaces (location_t, tree);
extern name_hint suggest_alternative_in_explicit_scope (location_t, tree,
tree);
+extern name_hint suggest_alternative_in_scoped_enum (tree, tree);
#endif /* GCC_CP_NAME_HINT_H */
diff --git a/gcc/cp/error.c b/gcc/cp/error.c
index 72b42bd..f9b0b99 100644
--- a/gcc/cp/error.c
+++ b/gcc/cp/error.c
@@ -182,6 +182,12 @@ dump_scope (cxx_pretty_printer *pp, tree scope, int flags)
if (scope == NULL_TREE)
return;
+ /* Enum values within an unscoped enum will be CONST_DECL with an
+ ENUMERAL_TYPE as their "scope". Use CP_TYPE_CONTEXT of the
+ ENUMERAL_TYPE, so as to print any enclosing namespace. */
+ if (UNSCOPED_ENUM_P (scope))
+ scope = CP_TYPE_CONTEXT (scope);
+
if (TREE_CODE (scope) == NAMESPACE_DECL)
{
if (scope != global_namespace)
@@ -190,7 +196,8 @@ dump_scope (cxx_pretty_printer *pp, tree scope, int flags)
pp_cxx_colon_colon (pp);
}
}
- else if (AGGREGATE_TYPE_P (scope))
+ else if (AGGREGATE_TYPE_P (scope)
+ || SCOPED_ENUM_P (scope))
{
dump_type (pp, scope, f);
pp_cxx_colon_colon (pp);
@@ -4261,7 +4268,21 @@ qualified_name_lookup_error (tree scope, tree name,
print_candidates (decl);
}
else
- error_at (location, "%qD is not a member of %qT", name, scope);
+ {
+ name_hint hint;
+ if (SCOPED_ENUM_P (scope))
+ hint = suggest_alternative_in_scoped_enum (name, scope);
+ if (const char *suggestion = hint.suggestion ())
+ {
+ gcc_rich_location richloc (location);
+ richloc.add_fixit_replace (suggestion);
+ error_at (&richloc,
+ "%qD is not a member of %qT; did you mean %qs?",
+ name, scope, suggestion);
+ }
+ else
+ error_at (location, "%qD is not a member of %qT", name, scope);
+ }
}
else if (scope != global_namespace)
{
diff --git a/gcc/cp/name-lookup.c b/gcc/cp/name-lookup.c
index 239bb01..cadf380 100644
--- a/gcc/cp/name-lookup.c
+++ b/gcc/cp/name-lookup.c
@@ -5396,8 +5396,8 @@ class suggest_alternatives : public deferred_diagnostic
};
/* A class for encapsulating the result of a search across
- multiple namespaces for an unrecognized name seen at a
- given source location. */
+ multiple namespaces (and scoped enums within them) for an
+ unrecognized name seen at a given source location. */
class namespace_hints
{
@@ -5408,6 +5408,8 @@ class namespace_hints
name_hint maybe_decorate_with_limit (name_hint);
private:
+ void maybe_add_candidate_for_scoped_enum (tree scoped_enum, tree name);
+
location_t m_loc;
tree m_name;
vec<tree> m_candidates;
@@ -5419,8 +5421,8 @@ class namespace_hints
bool m_limited;
};
-/* Constructor for namespace_hints. Search namespaces, looking for a match
- for unrecognized NAME seen at LOC. */
+/* Constructor for namespace_hints. Search namespaces and scoped enums,
+ looking for an exact match for unrecognized NAME seen at LOC. */
namespace_hints::namespace_hints (location_t loc, tree name)
: m_loc(loc), m_name (name)
@@ -5451,10 +5453,22 @@ namespace_hints::namespace_hints (location_t loc, tree
name)
for (tree decl = NAMESPACE_LEVEL (ns)->names;
decl; decl = TREE_CHAIN (decl))
- if (TREE_CODE (decl) == NAMESPACE_DECL
- && !DECL_NAMESPACE_ALIAS (decl)
- && !DECL_NAMESPACE_INLINE_P (decl))
- children.safe_push (decl);
+ {
+ if (TREE_CODE (decl) == NAMESPACE_DECL
+ && !DECL_NAMESPACE_ALIAS (decl)
+ && !DECL_NAMESPACE_INLINE_P (decl))
+ children.safe_push (decl);
+
+ /* Look for exact matches for NAME within scoped enums.
+ These aren't added to the worklist, and so don't count
+ against the search limit. */
+ if (TREE_CODE (decl) == TYPE_DECL)
+ {
+ tree type = TREE_TYPE (decl);
+ if (SCOPED_ENUM_P (type))
+ maybe_add_candidate_for_scoped_enum (type, name);
+ }
+ }
while (!m_limited && !children.is_empty ())
{
@@ -5522,11 +5536,32 @@ namespace_hints::maybe_decorate_with_limit (name_hint
hint)
return hint;
}
+/* Look inside SCOPED_ENUM for exact matches for NAME.
+ If one is found, add its CONST_DECL to m_candidates. */
+
+void
+namespace_hints::maybe_add_candidate_for_scoped_enum (tree scoped_enum,
+ tree name)
+{
+ gcc_assert (SCOPED_ENUM_P (scoped_enum));
+
+ for (tree iter = TYPE_VALUES (scoped_enum); iter; iter = TREE_CHAIN (iter))
+ {
+ tree id = TREE_PURPOSE (iter);
+ if (id == name)
+ {
+ m_candidates.safe_push (TREE_VALUE (iter));
+ return;
+ }
+ }
+}
+
/* Generate a name_hint at LOCATION for NAME, an IDENTIFIER_NODE for which
name lookup failed.
- Search through all available namespaces and generate a suggestion and/or
- a deferred diagnostic that lists possible candidate(s).
+ Search through all available namespaces and any scoped enums within them
+ and generate a suggestion and/or a deferred diagnostic that lists possible
+ candidate(s).
If no exact matches are found, and SUGGEST_MISSPELLINGS is true, then also
look for near-matches and suggest the best near-match, if there is one.
@@ -5910,6 +5945,23 @@ suggest_alternative_in_explicit_scope (location_t
location, tree name,
return name_hint ();
}
+/* Given NAME, look within SCOPED_ENUM for possible spell-correction
+ candidates. */
+
+name_hint
+suggest_alternative_in_scoped_enum (tree name, tree scoped_enum)
+{
+ gcc_assert (SCOPED_ENUM_P (scoped_enum));
+
+ best_match <tree, const char *> bm (name);
+ for (tree iter = TYPE_VALUES (scoped_enum); iter; iter = TREE_CHAIN (iter))
+ {
+ tree id = TREE_PURPOSE (iter);
+ bm.consider (IDENTIFIER_POINTER (id));
+ }
+ return name_hint (bm.get_best_meaningful_candidate (), NULL);
+}
+
/* Look up NAME (an IDENTIFIER_NODE) in SCOPE (either a NAMESPACE_DECL
or a class TYPE).
diff --git a/gcc/testsuite/g++.dg/lookup/suggestions-scoped-enums.C
b/gcc/testsuite/g++.dg/lookup/suggestions-scoped-enums.C
new file mode 100644
index 0000000..fa6e7cb
--- /dev/null
+++ b/gcc/testsuite/g++.dg/lookup/suggestions-scoped-enums.C
@@ -0,0 +1,110 @@
+// { dg-do compile { target c++11 } }
+// { dg-options "-fdiagnostics-show-caret" }
+
+/* Verify that we offer suggestions for misspelled values
+ in scoped enums, and for values from scoped enums that
+ are missing their scope.
+ Verify that we emit fix-it hints for those cases for
+ which we have adequate location information. */
+
+enum class vegetable { CARROT, TURNIP }; // { dg-line decl_of_vegetable }
+namespace pasta
+{
+ enum class shape { LASAGNA, LINGUINE, SPAGHETTI, TAGLIATELLE }; // { dg-line
decl_of_shape }
+}
+
+void misspelled_value_in_scoped_enum ()
+{
+ vegetable::TURNUP; // { dg-error "'TURNUP' is not a member of 'vegetable';
did you mean 'TURNIP'" }
+ /* { dg-begin-multiline-output "" }
+ vegetable::TURNUP;
+ ^~~~~~
+ TURNIP
+ { dg-end-multiline-output "" } */
+}
+
+void misspelled_value_using_explicit_ns ()
+{
+ pasta::shape::SPOOGHETTI; // { dg-error "'SPOOGHETTI' is not a member of
'pasta::shape'; did you mean 'SPAGHETTI'" }
+ /* { dg-begin-multiline-output "" }
+ pasta::shape::SPOOGHETTI;
+ ^~~~~~~~~~
+ SPAGHETTI
+ { dg-end-multiline-output "" } */
+}
+
+namespace pasta {
+void misspelled_value_using_implicit_ns ()
+{
+ shape::SPOOGHETTI; // { dg-error "'SPOOGHETTI' is not a member of
'pasta::shape'; did you mean 'SPAGHETTI'" }
+ /* { dg-begin-multiline-output "" }
+ shape::SPOOGHETTI;
+ ^~~~~~~~~~
+ SPAGHETTI
+ { dg-end-multiline-output "" } */
+}
+} // namespace pasta
+
+void unqualified_enum_in_global_ns ()
+{
+ CARROT; // { dg-error "'CARROT' was not declared in this scope; did you mean
'vegetable::CARROT'" }
+ /* { dg-begin-multiline-output "" }
+ CARROT;
+ ^~~~~~
+ vegetable::CARROT
+ { dg-end-multiline-output "" } */
+ // { dg-message "'vegetable::CARROT' declared here" "" { target *-*-* }
decl_of_vegetable }
+ /* { dg-begin-multiline-output "" }
+ enum class vegetable { CARROT, TURNIP };
+ ^~~~~~
+ { dg-end-multiline-output "" } */
+}
+
+void unqualified_enum_in_ns ()
+{
+ LASAGNA; // { dg-error "'LASAGNA' was not declared in this scope; did you
mean 'pasta::shape::LASAGNA'" }
+ /* { dg-begin-multiline-output "" }
+ LASAGNA;
+ ^~~~~~~
+ pasta::shape::LASAGNA
+ { dg-end-multiline-output "" } */
+ // { dg-message "'pasta::shape::LASAGNA' declared here" "" { target *-*-* }
decl_of_shape }
+ /* { dg-begin-multiline-output "" }
+ enum class shape { LASAGNA, LINGUINE, SPAGHETTI, TAGLIATELLE };
+ ^~~~~~~
+ { dg-end-multiline-output "" } */
+}
+
+/* We can't guarantee location information here, so don't expect a
+ fix-it hint. */
+
+void unqualified_enum_in_explicit_ns ()
+{
+ pasta::LINGUINE; // { dg-error "'LINGUINE' is not a member of 'pasta'; did
you mean 'pasta::shape::LINGUINE'" }
+ /* { dg-begin-multiline-output "" }
+ pasta::LINGUINE;
+ ^~~~~~~~
+ { dg-end-multiline-output "" } */
+ // { dg-message "'pasta::shape::LINGUINE' declared here" "" { target *-*-* }
decl_of_shape }
+ /* { dg-begin-multiline-output "" }
+ enum class shape { LASAGNA, LINGUINE, SPAGHETTI, TAGLIATELLE };
+ ^~~~~~~~
+ { dg-end-multiline-output "" } */
+}
+
+namespace pasta {
+void unqualified_enum_in_implicit_ns ()
+{
+ TAGLIATELLE; // { dg-error "'TAGLIATELLE' was not declared in this scope;
did you mean 'pasta::shape::TAGLIATELLE'" }
+ /* { dg-begin-multiline-output "" }
+ TAGLIATELLE;
+ ^~~~~~~~~~~
+ pasta::shape::TAGLIATELLE
+ { dg-end-multiline-output "" } */
+ // { dg-message "'pasta::shape::TAGLIATELLE' declared here" "" { target
*-*-* } decl_of_shape }
+ /* { dg-begin-multiline-output "" }
+ enum class shape { LASAGNA, LINGUINE, SPAGHETTI, TAGLIATELLE };
+ ^~~~~~~~~~~
+ { dg-end-multiline-output "" } */
+}
+}
diff --git a/gcc/testsuite/g++.dg/lookup/suggestions-unscoped-enums.C
b/gcc/testsuite/g++.dg/lookup/suggestions-unscoped-enums.C
new file mode 100644
index 0000000..0dcff88
--- /dev/null
+++ b/gcc/testsuite/g++.dg/lookup/suggestions-unscoped-enums.C
@@ -0,0 +1,91 @@
+// { dg-options "-fdiagnostics-show-caret" }
+
+enum { LASAGNA, SPAGHETTI };
+namespace outer_ns_a
+{
+ enum enum_in_outer_ns_a { STRAWBERRY, BANANA };
+ namespace inner_ns
+ {
+ enum enum_in_inner_ns { ELEPHANT, LION };
+ }
+}
+namespace outer_ns_b
+{
+ enum enum_in_outer_ns_b { NIGHT, DAY };
+}
+
+void misspelled_enum_in_global_ns ()
+{
+ SPOOGHETTI; // { dg-error "'SPOOGHETTI' was not declared in this scope; did
you mean 'SPAGHETTI'" }
+ /* { dg-begin-multiline-output "" }
+ SPOOGHETTI;
+ ^~~~~~~~~~
+ SPAGHETTI
+ { dg-end-multiline-output "" } */
+}
+
+void unqualified_enum_in_outer_ns ()
+{
+ BANANA; // { dg-error "'BANANA' was not declared in this scope; did you mean
'outer_ns_a::BANANA'" }
+ /* { dg-begin-multiline-output "" }
+ BANANA;
+ ^~~~~~
+ outer_ns_a::BANANA
+ { dg-end-multiline-output "" } */
+ /* { dg-begin-multiline-output "" }
+ enum enum_in_outer_ns_a { STRAWBERRY, BANANA };
+ ^~~~~~
+ { dg-end-multiline-output "" } */
+}
+
+namespace outer_ns_a
+{
+ void misspelled_unqualified_enum_in_outer_ns () {
+ BANANAS; // { dg-error "'BANANAS' was not declared in this scope; did you
mean 'BANANA'" }
+ /* { dg-begin-multiline-output "" }
+ BANANAS;
+ ^~~~~~~
+ BANANA
+ { dg-end-multiline-output "" } */
+ }
+};
+
+void unqualified_enum_in_inner_ns ()
+{
+ ELEPHANT; // { dg-error "'ELEPHANT' was not declared in this scope; did you
mean 'outer_ns_a::inner_ns::ELEPHANT'" }
+ /* { dg-begin-multiline-output "" }
+ ELEPHANT;
+ ^~~~~~~~
+ outer_ns_a::inner_ns::ELEPHANT
+ { dg-end-multiline-output "" } */
+ /* { dg-begin-multiline-output "" }
+ enum enum_in_inner_ns { ELEPHANT, LION };
+ ^~~~~~~~
+ { dg-end-multiline-output "" } */
+}
+
+void partially_qualified_enum_in_inner_ns ()
+{
+ outer_ns_a::ELEPHANT; // { dg-error "'ELEPHANT' is not a member of
'outer_ns_a'; did you mean 'outer_ns_a::inner_ns::ELEPHANT'" }
+ /* { dg-begin-multiline-output "" }
+ outer_ns_a::ELEPHANT;
+ ^~~~~~~~
+ { dg-end-multiline-output "" } */
+ /* { dg-begin-multiline-output "" }
+ enum enum_in_inner_ns { ELEPHANT, LION };
+ ^~~~~~~~
+ { dg-end-multiline-output "" } */
+}
+
+void wrongly_qualified_enum ()
+{
+ outer_ns_a::NIGHT; // { dg-error "'NIGHT' is not a member of 'outer_ns_a';
did you mean 'outer_ns_b::NIGHT'" }
+ /* { dg-begin-multiline-output "" }
+ outer_ns_a::NIGHT;
+ ^~~~~
+ { dg-end-multiline-output "" } */
+ /* { dg-begin-multiline-output "" }
+ enum enum_in_outer_ns_b { NIGHT, DAY };
+ ^~~~~
+ { dg-end-multiline-output "" } */
+}
--
1.8.5.3
