borrow works with generics

tests/run/tborrow.nim

@@ -0,0 +1,21 @@
+discard """
+  output: "4887 true"
+"""
+
+# test the new borrow feature that works with generics:
+
+proc `++`*[T: int | float](a, b: T): T =
+  result = a + b
+  
+type
+  DI = distinct int
+  DF = distinct float
+  DS = distinct string
+  
+proc `++`(x, y: DI): DI {.borrow.}
+proc `++`(x, y: DF): DF {.borrow.}
+
+proc `$`(x: DI): string {.borrow.}
+proc `$`(x: DF): string {.borrow.}
+
+echo  4544.DI ++ 343.di, " ", (4.5.df ++ 0.5.df).float == 5.0