remove bad type inference behavior for enum identifiers (2.0)

compiler/semexprs.nim

@@ -3037,14 +3037,6 @@ proc semExpr(c: PContext, n: PNode, flags: TExprFlags = {}, expectedType: PType
  case n.kind
  of nkIdent, nkAccQuoted:
  var s: PSym
- if expectedType != nil and (
- let expected = expectedType.skipTypes(abstractRange-{tyDistinct});
- expected.kind == tyEnum):
- let nameId = considerQuotedIdent(c, n).id
- for f in expected.n:
- if f.kind == nkSym and f.sym.name.id == nameId:
- s = f.sym
- break
  if s == nil:
  let checks = if efNoEvaluateGeneric in flags:
  {checkUndeclared, checkPureEnumFields}

tests/errmsgs/t21257.nim

@@ -1,5 +1,4 @@
 discard """
- action: compile
  cmd: "nim check $file" 
 """
 
@@ -16,5 +15,6 @@ type AC_WINCTRL_WINTSEL0* {.pure.} = enum
  BELOW = 0x2,
  OUTSIDE = 0x3,
 
-proc write*(WINTSEL0: AC_WINCTRL_WINTSEL0 = ABOVE) =
+proc write*(WINTSEL0: AC_WINCTRL_WINTSEL0 = ABOVE) = #[tt.Error
+ ^ ambiguous identifier: 'ABOVE']#
  discard

tests/lookups/tenumlocalsym.nim

@@ -0,0 +1,22 @@
+block:
+ type Enum = enum a, b
+
+ block:
+ let a = b
+ let x: Enum = a
+ doAssert x == b
+
+block:
+ type
+ Enum = enum
+ a = 2
+ b = 10
+
+ iterator items2(): Enum =
+ for a in [a, b]:
+ yield a
+
+ var s = newSeq[Enum]()
+ for i in items2():
+ s.add i
+ doAssert s == @[a, b]

tests/types/ttopdowninference.nim

@@ -119,8 +119,8 @@ when false: # unsupported
  doAssert x[1] == (cstring"def", 2.0'f32)
 
 block: # enum
- type Foo {.pure.} = enum a
- type Bar {.pure.} = enum a, b, c
+ type Foo = enum a
+ type Bar = enum a, b, c
 
  var s: seq[Bar] = @[a, b, c]