Use Levenshtein spelling suggestions in Fortran FE

gcc/fortran/ChangeLog

2017-10-19  Bernhard Reutner-Fischer  <aldot@gcc.gnu.org>

	* gfortran.h (gfc_lookup_function_fuzzy): New declaration.
	(gfc_closest_fuzzy_match): New declaration.
	(vec_push): New definition.
	* misc.c (gfc_closest_fuzzy_match): New definition.
	* resolve.c: Include spellcheck.h.
	(lookup_function_fuzzy_find_candidates): New static function.
	(lookup_uop_fuzzy_find_candidates): Likewise.
	(lookup_uop_fuzzy): Likewise.
	(resolve_operator) <INTRINSIC_USER>: Call lookup_uop_fuzzy.
	(gfc_lookup_function_fuzzy): New definition.
	(resolve_unknown_f): Call gfc_lookup_function_fuzzy.
	* interface.c (check_interface0): Likewise.
	(lookup_arg_fuzzy_find_candidates): New static function.
	(lookup_arg_fuzzy ): Likewise.
	(compare_actual_formal): Call lookup_arg_fuzzy.
	* symbol.c: Include spellcheck.h.
	(lookup_symbol_fuzzy_find_candidates): New static function.
	(lookup_symbol_fuzzy): Likewise.
	(gfc_set_default_type): Call lookup_symbol_fuzzy.
	(lookup_component_fuzzy_find_candidates): New static function.
	(lookup_component_fuzzy): Likewise.
	(gfc_find_component): Call lookup_component_fuzzy.

gcc/testsuite/ChangeLog

2017-10-19  Bernhard Reutner-Fischer  <aldot@gcc.gnu.org>

	* gfortran.dg/spellcheck-operator.f90: New testcase.
	* gfortran.dg/spellcheck-procedure_1.f90: New testcase.
	* gfortran.dg/spellcheck-procedure_2.f90: New testcase.
	* gfortran.dg/spellcheck-structure.f90: New testcase.
	* gfortran.dg/spellcheck-parameter.f90: New testcase.

From-SVN: r253877

1 files changed, 82 insertions, 4 deletions

diff --git a/gcc/fortran/symbol.c b/gcc/fortran/symbol.c
index 4c109fd..36abba5 100644
--- a/gcc/fortran/symbol.c
+++ b/gcc/fortran/symbol.c
@@ -245,6 +245,44 @@ gfc_get_default_type (const char *name, gfc_namespace *ns)
 }
 
 
+/* Recursively append candidate SYM to CANDIDATES.  Store the number of
+   candidates in CANDIDATES_LEN.  */
+
+static void
+lookup_symbol_fuzzy_find_candidates (gfc_symtree *sym,
+				     char **&candidates,
+				     size_t &candidates_len)
+{
+  gfc_symtree *p;
+
+  if (sym == NULL)
+    return;
+
+  if (sym->n.sym->ts.type != BT_UNKNOWN && sym->n.sym->ts.type != BT_PROCEDURE)
+    vec_push (candidates, candidates_len, sym->name);
+  p = sym->left;
+  if (p)
+    lookup_symbol_fuzzy_find_candidates (p, candidates, candidates_len);
+
+  p = sym->right;
+  if (p)
+    lookup_symbol_fuzzy_find_candidates (p, candidates, candidates_len);
+}
+
+
+/* Lookup symbol SYM_NAME fuzzily, taking names in SYMBOL into account.  */
+
+static const char*
+lookup_symbol_fuzzy (const char *sym_name, gfc_symbol *symbol)
+{
+  char **candidates = NULL;
+  size_t candidates_len = 0;
+  lookup_symbol_fuzzy_find_candidates (symbol->ns->sym_root, candidates,
+				       candidates_len);
+  return gfc_closest_fuzzy_match (sym_name, candidates);
+}
+
+
 /* Given a pointer to a symbol, set its type according to the first
    letter of its name.  Fails if the letter in question has no default
    type.  */
@@ -263,8 +301,14 @@ gfc_set_default_type (gfc_symbol *sym, int error_flag, gfc_namespace *ns)
     {
       if (error_flag && !sym->attr.untyped)
 	{
-	  gfc_error ("Symbol %qs at %L has no IMPLICIT type",
-		     sym->name, &sym->declared_at);
+	  const char *guessed = lookup_symbol_fuzzy (sym->name, sym);
+	  if (guessed)
+	    gfc_error ("Symbol %qs at %L has no IMPLICIT type"
+		       "; did you mean %qs?",
+		       sym->name, &sym->declared_at, guessed);
+	  else
+	    gfc_error ("Symbol %qs at %L has no IMPLICIT type",
+		       sym->name, &sym->declared_at);
 	  sym->attr.untyped = 1; /* Ensure we only give an error once.  */
 	}
 
@@ -2336,6 +2380,32 @@ find_union_component (gfc_symbol *un, const char *name,
 }
 
 
+/* Recursively append candidate COMPONENT structures to CANDIDATES.  Store
+   the number of total candidates in CANDIDATES_LEN.  */
+
+static void
+lookup_component_fuzzy_find_candidates (gfc_component *component,
+					char **&candidates,
+					size_t &candidates_len)
+{
+  for (gfc_component *p = component; p; p = p->next)
+    vec_push (candidates, candidates_len, p->name);
+}
+
+
+/* Lookup component MEMBER fuzzily, taking names in COMPONENT into account.  */
+
+static const char*
+lookup_component_fuzzy (const char *member, gfc_component *component)
+{
+  char **candidates = NULL;
+  size_t candidates_len = 0;
+  lookup_component_fuzzy_find_candidates (component, candidates,
+					  candidates_len);
+  return gfc_closest_fuzzy_match (member, candidates);
+}
+
+
 /* Given a derived type node and a component name, try to locate the
    component structure.  Returns the NULL pointer if the component is
    not found or the components are private.  If noaccess is set, no access
@@ -2433,8 +2503,16 @@ gfc_find_component (gfc_symbol *sym, const char *name,
     }
 
   if (p == NULL && !silent)
-    gfc_error ("%qs at %C is not a member of the %qs structure",
-	       name, sym->name);
+    {
+      const char *guessed = lookup_component_fuzzy (name, sym->components);
+      if (guessed)
+	gfc_error ("%qs at %C is not a member of the %qs structure"
+		   "; did you mean %qs?",
+		   name, sym->name, guessed);
+      else
+	gfc_error ("%qs at %C is not a member of the %qs structure",
+		   name, sym->name);
+    }
 
   /* Component was found; build the ultimate component reference. */
   if (p != NULL && ref)