diff --git a/.gitattributes b/.gitattributes
index 8e18770f9b..12ae660c5b 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -15181,6 +15181,10 @@ tests/test/tgenfunc20.pp svneol=native#text/pascal
 tests/test/tgenfunc21.pp svneol=native#text/pascal
 tests/test/tgenfunc22.pp svneol=native#text/pascal
 tests/test/tgenfunc23.pp svneol=native#text/pascal
+tests/test/tgenfunc24.pp svneol=native#text/pascal
+tests/test/tgenfunc25.pp svneol=native#text/pascal
+tests/test/tgenfunc26.pp svneol=native#text/pascal
+tests/test/tgenfunc27.pp svneol=native#text/pascal
 tests/test/tgenfunc3.pp svneol=native#text/pascal
 tests/test/tgenfunc4.pp svneol=native#text/pascal
 tests/test/tgenfunc5.pp svneol=native#text/pascal
diff --git a/compiler/pdecsub.pas b/compiler/pdecsub.pas
index 3f7998b21d..baf558743b 100644
--- a/compiler/pdecsub.pas
+++ b/compiler/pdecsub.pas
@@ -1066,7 +1066,8 @@ implementation
                            end
                          else if (srsym.typ=typesym) and
                              (sp_generic_dummy in srsym.symoptions) and
-                             (ttypesym(srsym).typedef.typ=undefineddef) then
+                             (ttypesym(srsym).typedef.typ=undefineddef) and
+                             not assigned(genericparams) then
                            begin
                              { this is a generic dummy symbol that has not yet
                                been used; so we rename the dummy symbol and continue
@@ -1162,12 +1163,21 @@ implementation
               end;
             if not assigned(dummysym) then
               begin
-                dummysym:=ctypesym.create(orgspnongen,cundefineddef.create(true));
+                { overloading generic routines with non-generic types is not
+                  allowed, so we create a procsym as dummy }
+                dummysym:=cprocsym.create(orgspnongen);
                 if assigned(astruct) then
                   astruct.symtable.insert(dummysym)
                 else
                   symtablestack.top.insert(dummysym);
-              end;
+              end
+            else if (dummysym.typ<>procsym) and
+                (
+                  { show error only for the declaration, not also the implementation }
+                  not assigned(astruct) or
+                  (symtablestack.top.symtablelevel<>main_program_level)
+                ) then
+              Message1(sym_e_duplicate_id,dummysym.realname);
             if not (sp_generic_dummy in dummysym.symoptions) then
               begin
                 include(dummysym.symoptions,sp_generic_dummy);
diff --git a/tests/test/tgenfunc24.pp b/tests/test/tgenfunc24.pp
new file mode 100644
index 0000000000..ca592be8d5
--- /dev/null
+++ b/tests/test/tgenfunc24.pp
@@ -0,0 +1,25 @@
+{ %FAIL }
+
+program tgenfunc24;
+
+{$mode delphi}
+
+type
+  TTest = class
+  public type
+    Test = class
+    end;
+
+  public
+    procedure Test<T>;
+  end;
+
+procedure TTest.Test<T>;
+begin
+
+end;
+
+begin
+
+end.
+
diff --git a/tests/test/tgenfunc25.pp b/tests/test/tgenfunc25.pp
new file mode 100644
index 0000000000..3728c37807
--- /dev/null
+++ b/tests/test/tgenfunc25.pp
@@ -0,0 +1,24 @@
+{ %FAIL }
+
+program tgenfunc25;
+
+{$mode delphi}
+
+type
+  TTest = class
+  public
+    procedure Test<T>;
+  public type
+    Test = class
+    end;
+  end;
+
+procedure TTest.Test<T>;
+begin
+
+end;
+
+begin
+
+end.
+
diff --git a/tests/test/tgenfunc26.pp b/tests/test/tgenfunc26.pp
new file mode 100644
index 0000000000..f0f34b9b13
--- /dev/null
+++ b/tests/test/tgenfunc26.pp
@@ -0,0 +1,24 @@
+{ %FAIL }
+
+unit tgenfunc26;
+
+{$mode objfpc}{$H+}
+
+interface
+
+generic procedure Test<T>;
+
+type
+  Test = record
+
+  end;
+
+implementation
+
+generic procedure Test<T>;
+begin
+
+end;
+
+end.
+
diff --git a/tests/test/tgenfunc27.pp b/tests/test/tgenfunc27.pp
new file mode 100644
index 0000000000..ea18a34fea
--- /dev/null
+++ b/tests/test/tgenfunc27.pp
@@ -0,0 +1,24 @@
+{ %FAIL }
+
+unit tgenfunc27;
+
+{$mode objfpc}{$H+}
+
+interface
+
+type
+  Test = record
+
+  end;
+
+generic procedure Test<T>;
+
+implementation
+
+generic procedure Test<T>;
+begin
+
+end;
+
+end.
+