Parameter name expansion fix for template functions.

Fix regression in 4.0.0 where a template function containing a parameter
with the same name as the function name led to the parameter name used in the
target language being incorrectly modified.

Closes #1602

3 files changed, 34 insertions, 11 deletions

diff --git a/CHANGES.current b/CHANGES.current
index b7d7fa3df..6b38059b8 100644
--- a/CHANGES.current
+++ b/CHANGES.current
@@ -7,6 +7,11 @@ the issue number to the end of the URL: https://github.com/swig/swig/issues/
 Version 4.0.1 (in progress)
 ===========================
 
+2019-08-01: wsfulton
+            #1602 Fix regression in 4.0.0 where a template function containing a parameter
+            with the same name as the function name led to the parameter name used in the
+            target language being incorrectly modified.
+
 2019-07-29: wsfulton
             Remove all generated files on error. Previously generated files were not removed,
             potentially breaking Makefiles using file dependencies, especially when -Werror
diff --git a/Examples/test-suite/typemap_template_parms.i b/Examples/test-suite/typemap_template_parms.i
index fd0f7f51a..90231e827 100644
--- a/Examples/test-suite/typemap_template_parms.i
+++ b/Examples/test-suite/typemap_template_parms.i
@@ -26,3 +26,16 @@ template<typename T> struct X {
 %}
 
 %template(Xint) X<int>;
+
+
+// The function name and parameter name are both 'labels'
+%inline %{
+template <typename T>
+void labels(T labels) {}
+void voido(int vooo) {}
+%}
+
+// TODO: R has a problem with parameter names clashing with the function name
+#if !defined(SWIGR)
+%template(ShortLabels) labels<short>;
+#endif
diff --git a/Source/CParse/templ.c b/Source/CParse/templ.c
index 6b1a27014..22d49fac5 100644
--- a/Source/CParse/templ.c
+++ b/Source/CParse/templ.c
@@ -26,14 +26,19 @@ void SwigType_template_init() {
 }
 
 
-static void add_parms(ParmList *p, List *patchlist, List *typelist) {
+static void add_parms(ParmList *p, List *patchlist, List *typelist, int is_pattern) {
   while (p) {
     SwigType *ty = Getattr(p, "type");
     SwigType *val = Getattr(p, "value");
-    SwigType *name = Getattr(p, "name");
     Append(typelist, ty);
     Append(typelist, val);
-    Append(typelist, name);
+    if (is_pattern) {
+      /* Typemap patterns are not simple parameter lists.
+       * Output style ("out", "ret" etc) typemap names can be
+       * qualified names and so may need template expansion */
+      SwigType *name = Getattr(p, "name");
+      Append(typelist, name);
+    }
     Append(patchlist, val);
     p = nextSibling(p);
   }
@@ -108,8 +113,8 @@ static void cparse_template_expand(Node *templnode, Node *n, String *tname, Stri
       Append(typelist, Getattr(n, "name"));
     }
 
-    add_parms(Getattr(n, "parms"), cpatchlist, typelist);
-    add_parms(Getattr(n, "throws"), cpatchlist, typelist);
+    add_parms(Getattr(n, "parms"), cpatchlist, typelist, 0);
+    add_parms(Getattr(n, "throws"), cpatchlist, typelist, 0);
 
   } else if (Equal(nodeType, "class")) {
     /* Patch base classes */
@@ -175,8 +180,8 @@ static void cparse_template_expand(Node *templnode, Node *n, String *tname, Stri
     }
     Append(cpatchlist, Getattr(n, "code"));
     Append(typelist, Getattr(n, "decl"));
-    add_parms(Getattr(n, "parms"), cpatchlist, typelist);
-    add_parms(Getattr(n, "throws"), cpatchlist, typelist);
+    add_parms(Getattr(n, "parms"), cpatchlist, typelist, 0);
+    add_parms(Getattr(n, "throws"), cpatchlist, typelist, 0);
   } else if (Equal(nodeType, "destructor")) {
     /* We only need to patch the dtor of the template itself, not the destructors of any nested classes, so check that the parent of this node is the root
      * template node, with the special exception for %extend which adds its methods under an intermediate node. */
@@ -217,10 +222,10 @@ static void cparse_template_expand(Node *templnode, Node *n, String *tname, Stri
     Append(cpatchlist, Getattr(n, "code"));
     Append(typelist, Getattr(n, "type"));
     Append(typelist, Getattr(n, "decl"));
-    add_parms(Getattr(n, "parms"), cpatchlist, typelist);
-    add_parms(Getattr(n, "kwargs"), cpatchlist, typelist);
-    add_parms(Getattr(n, "pattern"), cpatchlist, typelist);
-    add_parms(Getattr(n, "throws"), cpatchlist, typelist);
+    add_parms(Getattr(n, "parms"), cpatchlist, typelist, 0);
+    add_parms(Getattr(n, "kwargs"), cpatchlist, typelist, 0);
+    add_parms(Getattr(n, "pattern"), cpatchlist, typelist, 1);
+    add_parms(Getattr(n, "throws"), cpatchlist, typelist, 0);
     cn = firstChild(n);
     while (cn) {
       cparse_template_expand(templnode, cn, tname, rname, templateargs, patchlist, typelist, cpatchlist);