Fix deduction of partially specialized template parameters

when the specialized parameter is non-trivial, used in a wrapped method
and the type to %template uses typedefs. For example:

  typedef double & DoubleRef;
  template <typename T> struct XX {};
  template <typename T> struct XX<T &> { void fn(T t) {} };
  %template(XXD) XX<DoubleRef>;

The type of the parameter in the instantiated template for fn is now correctly deduced
as double.

4 files changed, 43 insertions, 25 deletions

diff --git a/CHANGES.current b/CHANGES.current
index 62b609bc9..54813b0d3 100644
--- a/CHANGES.current
+++ b/CHANGES.current
@@ -11,6 +11,19 @@ Version 4.2.0 (in progress)
 	    #2492 [python] Fix unused parameter warnings for self parameter in
 	    generated C/C++ wrapper code.
 
+2023-01-14: wsfulton
+            Fix deduction of partially specialized template parameters when the specialized
+            parameter is non-trivial, used in a wrapped method and the type to %template uses
+            typedefs. For example:
+
+              typedef double & DoubleRef;
+              template <typename T> struct XX {};
+              template <typename T> struct XX<T &> { void fn(T t) {} };
+              %template(XXD) XX<DoubleRef>;
+
+            The type of the parameter in the instantiated template for fn is now correctly deduced
+            as double.
+
 2023-01-03: wsfulton
             #983 Fix seg fault when instantiating templates with parameters that are function
             parameters containing templates, such as:
diff --git a/Examples/test-suite/java/template_partial_specialization_typedef_runme.java b/Examples/test-suite/java/template_partial_specialization_typedef_runme.java
index 04653cdc0..008367c7a 100644
--- a/Examples/test-suite/java/template_partial_specialization_typedef_runme.java
+++ b/Examples/test-suite/java/template_partial_specialization_typedef_runme.java
@@ -12,12 +12,15 @@ public class template_partial_specialization_typedef_runme {
   }
 
   public static void main(String argv[]) {
+    double dub = 11.1;
+    Concrete concrete = new Concrete();
+
     // One parameter tests
     new A().a();
-    new B().b();
-    new C().c();
-    new D().d();
-    new E().e();
+    new B().b(); new B().bb(dub);
+    new C().c(); new C().cc(dub);
+    new D().d(); new D().dd(dub);
+    new E().e(); new E().ee(dub);
 
     new F().f();
     new G().g();
@@ -28,10 +31,10 @@ public class template_partial_specialization_typedef_runme {
     new M().m();
     new N().n();
 
-    new BB().b();
-    new BBB().b();
-    new BBBB().b();
-    new BBBBB().b();
+    new BB().b(); new BB().bb(true);
+    new BBB().b(); new BBB().bb('A');
+    new BBBB().b(); new BBBB().bb((short)12);
+    new BBBBB().b(); new BBBBB().bb(123);
 
     new B1().b();
     new B2().b();
@@ -40,18 +43,18 @@ public class template_partial_specialization_typedef_runme {
 
     // Two parameter tests
     new A_().a();
-    new B_().b();
-    new C_().c();
-    new D_().d();
+    new B_().b(); new B_().bbb(dub);
+    new C_().c(); new C_().ccc(dub);
+    new D_().d(); new D_().ddd(123);
     new E_().e();
     new F_().f();
     new G_().g();
 
-    new C1_().c();
-    new C2_().c();
-    new C3_().c();
-    new C4_().c();
-    new B1_().b();
+    new C1_().c(); new C1_().ccc(concrete);
+    new C2_().c(); new C2_().ccc(concrete);
+    new C3_().c(); new C3_().ccc(concrete);
+    new C4_().c(); new C4_().ccc(concrete);
+    new B1_().b(); new B1_().bbb(concrete);
     new E1_().e();
     new E2_().e();
   }
diff --git a/Examples/test-suite/template_partial_specialization_typedef.i b/Examples/test-suite/template_partial_specialization_typedef.i
index 6f8a11591..04475da1a 100644
--- a/Examples/test-suite/template_partial_specialization_typedef.i
+++ b/Examples/test-suite/template_partial_specialization_typedef.i
@@ -30,10 +30,10 @@ namespace TypeDef {
 }
 namespace One {
   template <typename T> struct OneParm                  { void a() {} };
-  template <typename T> struct OneParm<T *>             { void b() {} };
-  template <typename T> struct OneParm<T &>             { void c() {} };
-  template <typename T> struct OneParm<T const &>       { void d() {} };
-  template <typename T> struct OneParm<T * const &>     { void e() {} };
+  template <typename T> struct OneParm<T *>             { void b() {} void bb(const T &t) {} };
+  template <typename T> struct OneParm<T &>             { void c() {} void cc(const T &t) {} };
+  template <typename T> struct OneParm<T const &>       { void d() {} void dd(const T &t) {} };
+  template <typename T> struct OneParm<T * const &>     { void e() {} void ee(const T &t) {} };
 
   template <>           struct OneParm<int>             { void f() {} };
   template <>           struct OneParm<int * const &>   { void g() {} };
@@ -90,10 +90,10 @@ namespace One {
 struct Concrete {};
 namespace Two {
   template <typename T1, typename T2> struct TwoParm                          { void a() {} };
-  template <typename T1, typename T2> struct TwoParm<T1 *, T2 *>              { void b() {} };
-  template <typename T1, typename T2> struct TwoParm<T1 *, const T2 *>        { void c() {} };
-  template <typename T1, typename T2> struct TwoParm<const T1 *, const T2 *>  { void d() {} };
-  template <typename T1>              struct TwoParm<T1 *, int *>             { void e() {} };
+  template <typename T1, typename T2> struct TwoParm<T1 *, T2 *>              { void b() {} void bbb(const T2 &t) {} };
+  template <typename T1, typename T2> struct TwoParm<T1 *, const T2 *>        { void c() {} void ccc(const T2 &t) {} };
+  template <typename T1, typename T2> struct TwoParm<const T1 *, const T2 *>  { void d() {} void ddd(const T2 &t) {} };
+  template <typename T1>              struct TwoParm<T1 *, int *>             { void e() {} /*void eee(const T1 &t) {} TODO */};
   template <typename T1>              struct TwoParm<T1, int>                 { void f() {} };
   template <>                         struct TwoParm<int *, const int *>      { void g() {} };
 }
diff --git a/Source/CParse/templ.c b/Source/CParse/templ.c
index 718e5ddb8..7a4d0cf4f 100644
--- a/Source/CParse/templ.c
+++ b/Source/CParse/templ.c
@@ -452,10 +452,12 @@ int Swig_cparse_template_expand(Node *n, String *rname, ParmList *tparms, Symtab
       ptype = Getattr(p, "type");
       tptype = Getattr(tp, "type");
       if (ptype && tptype) {
-	partial_type = partial_arg(tptype, ptype);
+	SwigType *ty = Swig_symbol_typedef_reduce(tptype, tscope);
+	partial_type = partial_arg(ty, ptype);
 	/*      Printf(stdout,"partial '%s' '%s'  ---> '%s'\n", tptype, ptype, partial_type); */
 	Setattr(tp, "type", partial_type);
 	Delete(partial_type);
+	Delete(ty);
       }
       p = nextSibling(p);
       tp = nextSibling(tp);