type with same name in different scope now works (#17710)

* type with same name in different scope now works
* fix tests/enum/tenum.nim which was wrong because it was affected by this bug

tests/ccgbugs/tsamename3.nim

@@ -0,0 +1,111 @@
+block: # bug #15526
+  block:
+    type Foo = ref object
+      x1: int
+    let f1 = Foo(x1: 1)
+  block:
+    type Foo = ref object
+      x2: int
+    let f2 = Foo(x2: 2)
+
+block: # ditto
+  template fn() =
+    block:
+      type Foo = ref object
+        x1: int
+      let f1 = Foo(x1: 1)
+      doAssert f1.x1 == 1
+    block:
+      type Foo = ref object
+        x2: int
+      let f2 = Foo(x2: 2)
+      doAssert f2.x2 == 2
+  static: fn()
+  fn()
+
+block: # bug #17162
+  template fn =
+    var ret: string
+    block:
+      type A = enum a0, a1, a2
+      for ai in A:
+        ret.add $ai
+    block:
+      type A = enum b0, b1, b2, b3
+      for ai in A:
+        ret.add $ai
+    doAssert ret == "a0a1a2b0b1b2b3"
+
+  static: fn() # ok
+  fn() # was bug
+
+block: # ditto
+  proc fn =
+    var ret: string
+    block:
+      type A = enum a0, a1, a2
+      for ai in A:
+        ret.add $ai
+    block:
+      type A = enum b0, b1, b2, b3
+      for ai in A:
+        ret.add $ai
+    doAssert ret == "a0a1a2b0b1b2b3"
+
+  static: fn() # ok
+  fn() # was bug
+
+block: # bug #5170
+  block:
+    type Foo = object
+      x1: int
+    let f1 = Foo(x1: 1)
+  block:
+    type Foo = object
+      x2: int
+    let f2 = Foo(x2: 2)
+
+block: # ditto
+  block:
+    type Foo = object
+      bar: bool
+    var f1: Foo
+
+  block:
+    type Foo = object
+      baz: int
+    var f2: Foo
+    doAssert f2.baz == 0
+
+  block:
+    template fn() =
+      block:
+        type Foo = object
+          x1: int
+        let f1 = Foo(x1: 1)
+        doAssert f1.x1 == 1
+      block:
+        type Foo = object
+          x2: int
+        let f2 = Foo(x2: 2)
+        doAssert f2.x2 == 2
+    static: fn()
+    fn()
+
+when true: # ditto, refs https://github.com/nim-lang/Nim/issues/5170#issuecomment-582712132
+  type Foo1 = object # at top level
+    bar: bool
+  var f1: Foo1
+
+  block:
+    type Foo1 = object
+      baz: int
+    var f2: Foo1
+    doAssert f2.baz == 0
+
+block: # make sure `hashType` doesn't recurse infinitely
+  type
+    PFoo = ref object
+      a, b: PFoo
+      c: int
+  var a: PFoo