supports default for range types using firstOrd with nimPreviewRangeDefault (#23950)

ref https://github.com/nim-lang/Nim/issues/23943

compiler/sem.nim

@@ -651,7 +651,8 @@ proc defaultFieldsForTheUninitialized(c: PContext, recNode: PNode, checkDefault:
 
 proc defaultNodeField(c: PContext, a: PNode, aTyp: PType, checkDefault: bool): PNode =
   let aTypSkip = aTyp.skipTypes(defaultFieldsSkipTypes)
-  if aTypSkip.kind == tyObject:
+  case aTypSkip.kind
+  of tyObject:
     let child = defaultFieldsForTheUninitialized(c, aTypSkip.n, checkDefault)
     if child.len > 0:
       var asgnExpr = newTree(nkObjConstr, newNodeIT(nkType, a.info, aTyp))
@@ -660,7 +661,7 @@ proc defaultNodeField(c: PContext, a: PNode, aTyp: PType, checkDefault: bool): P
       result = semExpr(c, asgnExpr)
     else:
       result = nil
-  elif aTypSkip.kind == tyArray:
+  of tyArray:
     let child = defaultNodeField(c, a, aTypSkip[1], checkDefault)
 
     if child != nil:
@@ -673,7 +674,7 @@ proc defaultNodeField(c: PContext, a: PNode, aTyp: PType, checkDefault: bool): P
       result.typ = aTyp
     else:
       result = nil
-  elif aTypSkip.kind == tyTuple:
+  of tyTuple:
     var hasDefault = false
     if aTypSkip.n != nil:
       let children = defaultFieldsForTuple(c, aTypSkip.n, hasDefault, checkDefault)
@@ -686,6 +687,12 @@ proc defaultNodeField(c: PContext, a: PNode, aTyp: PType, checkDefault: bool): P
         result = nil
     else:
       result = nil
+  of tyRange:
+    if c.graph.config.isDefined("nimPreviewRangeDefault"):
+      result = newIntNode(nkIntLit, firstOrd(c.config, aTypSkip))
+      result.typ = aTyp
+    else:
+      result = nil
   else:
     result = nil
 

tests/objects/tobject_default_value.nim

@@ -121,7 +121,7 @@ template main {.dirty.} =
       rVal: R = default(R) # Works fine
       objVal = default(Obj)
 
-    doAssert rVal == 0 # it should be 1
+    doAssert rVal == 1
     doAssert objVal.r == 1
 
   block: # bug #16744
@@ -134,7 +134,7 @@ template main {.dirty.} =
       rVal: R = default(R) # Works fine
       objVal = Obj()
 
-    doAssert rVal == 0 # it should be 1
+    doAssert rVal == 1 # it should be 1
     doAssert objVal.r == 1
 
   block: # bug #3608
@@ -745,5 +745,19 @@ template main {.dirty.} =
       doAssert b.list[North] == 1
 
 
+  block:
+    type
+      range1 = range[1..10]
+      range2 = range[-1..10]
+
+    proc foo =
+      doAssert default(range1) == 1
+      doAssert default(range2) == -1
+
+      let s = default(array[5, range1])
+      doAssert s == [range1 1, 1, 1, 1, 1]
+
+    foo()
+
 static: main()
 main()