Merge tests into a larger file (part 3 of ∞: generics) (#9347)

* merge generics issues tests
* merge tgeneric
* merge test with local imports
* merge tcan tests
* merge matcher tests
* more issue tests merged
* one more tcan test
* merge various small tests into one file
* add a test for #3717

tests/generics/tcan.nim

@@ -0,0 +1,46 @@
+discard """
+  output: '''
+'''
+"""
+
+# Created by Eric Doughty-Papassideris on 2011-02-16.
+
+block talias_generic:
+  type
+    TGen[T] = object
+    TGen2[T] = TGen[T]
+
+
+block talias_specialised:
+  type
+    TGen[T] = object
+    TSpef = TGen[string]
+  var s: TSpef
+
+
+block tinherit:
+  type
+    TGen[T] = object of RootObj
+      x, y: T
+    TSpef[T] = object of TGen[T]
+
+  var s: TSpef[float]
+  s.x = 0.4
+  s.y = 0.6
+
+
+block tspecialise:
+  type
+    TGen[T] = object {.inheritable.}
+    TSpef = object of TGen[string]
+
+
+block tspecialised_equivalent:
+  type
+    TGen[T] = tuple[a: T]
+    TSpef = tuple[a: string]
+
+  var
+    a: TGen[string]
+    b: TSpef
+  a = b