This is similar to the field-name part of the v2 patch:
https://gcc.gnu.org/ml/gcc-patches/2015-09/msg01090.html
with the following changes:
- don't call unit tests from lookup_field_fuzzy
(instead, see patch 1 in the kit)
- use a cutoff: if more than half of the letters
were misspelled, the suggestion is likely to
be meaningless, so don't offer it.
- more test coverage
- deferral of the hints for type-name lookup (this can
wait to a later patch, since it seemed more
controversial)
gcc/c/ChangeLog:
* c-typeck.c: Include spellcheck.h.
(lookup_field_fuzzy_find_candidates): New function.
(lookup_field_fuzzy): New function.
(build_component_ref): If the field was not found, try using
lookup_field_fuzzy and potentially offer a suggestion.
gcc/testsuite/ChangeLog:
* gcc.dg/spellcheck-fields.c: New file.
---
gcc/c/c-typeck.c | 74 +++++++++++++++++++++++++++++++-
gcc/testsuite/gcc.dg/spellcheck-fields.c | 63 +++++++++++++++++++++++++++
2 files changed, 136 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/gcc.dg/spellcheck-fields.c
diff --git a/gcc/c/c-typeck.c b/gcc/c/c-typeck.c
index 61c5313..0660610 100644
--- a/gcc/c/c-typeck.c
+++ b/gcc/c/c-typeck.c
@@ -54,6 +54,7 @@ along with GCC; see the file COPYING3. If not see
#include "c-family/c-ubsan.h"
#include "cilk.h"
#include "gomp-constants.h"
+#include "spellcheck.h"
/* Possible cases of implicit bad conversions. Used to select
diagnostic messages in convert_for_assignment. */
@@ -2249,6 +2250,72 @@ lookup_field (tree type, tree component)
return tree_cons (NULL_TREE, field, NULL_TREE);
}
+/* Recursively append candidate IDENTIFIER_NODEs to CANDIDATES. */
+
+static void
+lookup_field_fuzzy_find_candidates (tree type, tree component,
+ vec<tree> *candidates)
+{
+ tree field;
+ for (field = TYPE_FIELDS (type); field; field = DECL_CHAIN (field))
+ {
+ if (DECL_NAME (field) == NULL_TREE
+ && (TREE_CODE (TREE_TYPE (field)) == RECORD_TYPE
+ || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE))
+ {
+ lookup_field_fuzzy_find_candidates (TREE_TYPE (field),
+ component,
+ candidates);
+ }
+
+ if (DECL_NAME (field))
+ candidates->safe_push (DECL_NAME (field));
+ }
+}
+
+/* Like "lookup_field", but find the closest matching IDENTIFIER_NODE,
+ rather than returning a TREE_LIST for an exact match. */
+
+static tree
+lookup_field_fuzzy (tree type, tree component)
+{
+ gcc_assert (TREE_CODE (component) == IDENTIFIER_NODE);
+
+ /* First, gather a list of candidates. */
+ auto_vec <tree> candidates;
+
+ lookup_field_fuzzy_find_candidates (type, component,
+ &candidates);
+
+ /* Now determine which is closest. */
+ int i;
+ tree identifier;
+ tree best_identifier = NULL;
+ edit_distance_t best_distance = MAX_EDIT_DISTANCE;
+ FOR_EACH_VEC_ELT (candidates, i, identifier)
+ {
+ gcc_assert (TREE_CODE (identifier) == IDENTIFIER_NODE);
+ edit_distance_t dist = levenshtein_distance (component, identifier);
+ if (dist < best_distance)
+ {
+ best_distance = dist;
+ best_identifier = identifier;
+ }
+ }
+
+ /* If more than half of the letters were misspelled, the suggestion is
+ likely to be meaningless. */
+ if (best_identifier)
+ {
+ unsigned int cutoff = MAX (IDENTIFIER_LENGTH (component),
+ IDENTIFIER_LENGTH (best_identifier)) / 2;
+ if (best_distance > cutoff)
+ return NULL;
+ }
+
+ return best_identifier;
+}
+
/* Make an expression to refer to the COMPONENT field of structure or
union value DATUM. COMPONENT is an IDENTIFIER_NODE. LOC is the
location of the COMPONENT_REF. */
@@ -2284,7 +2351,12 @@ build_component_ref (location_t loc, tree datum, tree
component)
if (!field)
{
- error_at (loc, "%qT has no member named %qE", type, component);
+ tree guessed_id = lookup_field_fuzzy (type, component);
+ if (guessed_id)
+ error_at (loc, "%qT has no member named %qE; did you mean %qE?",
+ type, component, guessed_id);
+ else
+ error_at (loc, "%qT has no member named %qE", type, component);
return error_mark_node;
}
diff --git a/gcc/testsuite/gcc.dg/spellcheck-fields.c
b/gcc/testsuite/gcc.dg/spellcheck-fields.c
new file mode 100644
index 0000000..01be550
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/spellcheck-fields.c
@@ -0,0 +1,63 @@
+/* { dg-do compile } */
+
+struct foo
+{
+ int foo;
+ int bar;
+ int baz;
+};
+
+int test (struct foo *ptr)
+{
+ return ptr->m_bar; /* { dg-error "'struct foo' has no member named 'm_bar';
did you mean 'bar'?" } */
+}
+
+int test2 (void)
+{
+ struct foo instance = {0, 0, 0};
+ return instance.m_bar; /* { dg-error "'struct foo' has no member named
'm_bar'; did you mean 'bar'?" } */
+}
+
+struct s {
+ struct j { int aa; } kk;
+ int ab;
+};
+
+void test3 (struct s x)
+{
+ x.ac; /* { dg-error "'struct s' has no member named 'ac'; did you mean
'ab'?" } */
+}
+
+int test4 (struct foo *ptr)
+{
+ return sizeof (ptr->foa); /* { dg-error "'struct foo' has no member named
'foa'; did you mean 'foo'?" } */
+}
+
+/* Verify that we don't offer nonsensical suggestions. */
+
+int test5 (struct foo *ptr)
+{
+ return ptr->this_is_unlike_any_of_the_fields; /* { dg-bogus "did you mean"
} */
+ /* { dg-error "has no member named" "" { target *-*-* } 40 } */
+}
+
+union u
+{
+ int color;
+ int shape;
+};
+
+int test6 (union u *ptr)
+{
+ return ptr->colour; /* { dg-error "'union u' has no member named 'colour';
did you mean 'color'?" } */
+}
+
+struct has_anon
+{
+ struct { int color; } s;
+};
+
+int test7 (struct has_anon *ptr)
+{
+ return ptr->s.colour; /* { dg-error "'struct <anonymous>' has no member
named 'colour'; did you mean 'color'?" } */
+}
--
1.8.5.3
