remove conflicting default call in tables.getOrDefault (#24265)

fixes #23587

As explained in the issue, `getOrDefault` has a parameter named
`default` that can be a proc after generic instantiation. But the
parameter having a proc type [overrides all other
overloads](https://github.com/nim-lang/Nim/blob/f73e03b1323cf3ed65d6996f43c8e6891c40f924/compiler/semexprs.nim#L1203)
including the magic `system.default` overload and causes a compile error
if the proc doesn't match the normal use of `default`. To fix this, the
`result = default(B)` initializer call is removed because it's not
needed, `result` is always set in `getOrDefaultImpl` when a default
value is provided.

This is still a suspicious behavior of the compiler but `tables` working
has a higher priority.

compiler/docgen.nim

@@ -115,7 +115,7 @@ proc add(dest: var ItemPre, str: string) = dest.add ItemFragment(isRst: false, s
 
 proc addRstFileIndex(d: PDoc, fileIndex: lineinfos.FileIndex): rstast.FileIndex =
   let invalid = rstast.FileIndex(-1)
-  result = d.nimToRstFid.getOrDefault(fileIndex, default = invalid)
+  result = d.nimToRstFid.getOrDefault(fileIndex, invalid)
   if result == invalid:
     let fname = toFullPath(d.conf, fileIndex)
     result = addFilename(d.sharedState, fname)

lib/packages/docutils/rst.nim

@@ -507,7 +507,7 @@ proc len(filenames: RstFileTable): int = filenames.idxToFilename.len
 proc addFilename*(s: PRstSharedState, file1: string): FileIndex =
   ## Returns index of filename, adding it if it has not been used before
   let nextIdx = s.filenames.len.FileIndex
-  result = getOrDefault(s.filenames.filenameToIdx, file1, default = nextIdx)
+  result = getOrDefault(s.filenames.filenameToIdx, file1, nextIdx)
   if result == nextIdx:
     s.filenames.filenameToIdx[file1] = result
     s.filenames.idxToFilename.add file1

lib/pure/collections/tables.nim

@@ -419,9 +419,9 @@ proc getOrDefault*[A, B](t: Table[A, B], key: A): B =
   result = default(B)
   getOrDefaultImpl(t, key)
 
-proc getOrDefault*[A, B](t: Table[A, B], key: A, default: B): B =
+proc getOrDefault*[A, B](t: Table[A, B], key: A, def: B): B =
   ## Retrieves the value at `t[key]` if `key` is in `t`.
-  ## Otherwise, `default` is returned.
+  ## Otherwise, `def` is returned.
   ##
   ## See also:
   ## * `[] proc<#[],Table[A,B],A>`_ for retrieving a value of a key
@@ -434,8 +434,7 @@ proc getOrDefault*[A, B](t: Table[A, B], key: A, default: B): B =
     let a = {'a': 5, 'b': 9}.toTable
     doAssert a.getOrDefault('a', 99) == 5
     doAssert a.getOrDefault('z', 99) == 99
-  result = default(B)
-  getOrDefaultImpl(t, key, default)
+  getOrDefaultImpl(t, key, def)
 
 proc mgetOrPut*[A, B](t: var Table[A, B], key: A, val: B): var B =
   ## Retrieves value at `t[key]` or puts `val` if not present, either way
@@ -972,9 +971,9 @@ proc getOrDefault*[A, B](t: TableRef[A, B], key: A): B =
 
   getOrDefault(t[], key)
 
-proc getOrDefault*[A, B](t: TableRef[A, B], key: A, default: B): B =
+proc getOrDefault*[A, B](t: TableRef[A, B], key: A, def: B): B =
   ## Retrieves the value at `t[key]` if `key` is in `t`.
-  ## Otherwise, `default` is returned.
+  ## Otherwise, `def` is returned.
   ##
   ## See also:
   ## * `[] proc<#[],TableRef[A,B],A>`_ for retrieving a value of a key
@@ -988,7 +987,7 @@ proc getOrDefault*[A, B](t: TableRef[A, B], key: A, default: B): B =
     doAssert a.getOrDefault('a', 99) == 5
     doAssert a.getOrDefault('z', 99) == 99
 
-  getOrDefault(t[], key, default)
+  getOrDefault(t[], key, def)
 
 proc mgetOrPut*[A, B](t: TableRef[A, B], key: A, val: B): var B =
   ## Retrieves value at `t[key]` or puts `val` if not present, either way
@@ -1491,9 +1490,9 @@ proc getOrDefault*[A, B](t: OrderedTable[A, B], key: A): B =
   result = default(B)
   getOrDefaultImpl(t, key)
 
-proc getOrDefault*[A, B](t: OrderedTable[A, B], key: A, default: B): B =
+proc getOrDefault*[A, B](t: OrderedTable[A, B], key: A, def: B): B =
   ## Retrieves the value at `t[key]` if `key` is in `t`.
-  ## Otherwise, `default` is returned.
+  ## Otherwise, `def` is returned.
   ##
   ## See also:
   ## * `[] proc<#[],OrderedTable[A,B],A>`_ for retrieving a value of a key
@@ -1506,8 +1505,7 @@ proc getOrDefault*[A, B](t: OrderedTable[A, B], key: A, default: B): B =
     let a = {'a': 5, 'b': 9}.toOrderedTable
     doAssert a.getOrDefault('a', 99) == 5
     doAssert a.getOrDefault('z', 99) == 99
-  result = default(B)
-  getOrDefaultImpl(t, key, default)
+  getOrDefaultImpl(t, key, def)
 
 proc mgetOrPut*[A, B](t: var OrderedTable[A, B], key: A, val: B): var B =
   ## Retrieves value at `t[key]` or puts `val` if not present, either way
@@ -1992,9 +1990,9 @@ proc getOrDefault*[A, B](t: OrderedTableRef[A, B], key: A): B =
 
   getOrDefault(t[], key)
 
-proc getOrDefault*[A, B](t: OrderedTableRef[A, B], key: A, default: B): B =
+proc getOrDefault*[A, B](t: OrderedTableRef[A, B], key: A, def: B): B =
   ## Retrieves the value at `t[key]` if `key` is in `t`.
-  ## Otherwise, `default` is returned.
+  ## Otherwise, `def` is returned.
   ##
   ## See also:
   ## * `[] proc<#[],OrderedTableRef[A,B],A>`_ for retrieving a value of a key
@@ -2008,7 +2006,7 @@ proc getOrDefault*[A, B](t: OrderedTableRef[A, B], key: A, default: B): B =
     doAssert a.getOrDefault('a', 99) == 5
     doAssert a.getOrDefault('z', 99) == 99
 
-  getOrDefault(t[], key, default)
+  getOrDefault(t[], key, def)
 
 proc mgetOrPut*[A, B](t: OrderedTableRef[A, B], key: A, val: B): var B =
   ## Retrieves value at `t[key]` or puts `val` if not present, either way
@@ -2320,9 +2318,9 @@ proc rawGet[A](t: CountTable[A], key: A): int =
     h = nextTry(h, high(t.data))
   result = -1 - h # < 0 => MISSING; insert idx = -1 - result
 
-template ctget(t, key, default: untyped): untyped =
+template ctget(t, key, def: untyped): untyped =
   var index = rawGet(t, key)
-  result = if index >= 0: t.data[index].val else: default
+  result = if index >= 0: t.data[index].val else: def
 
 proc inc*[A](t: var CountTable[A], key: A, val = 1)
 
@@ -2447,15 +2445,15 @@ proc contains*[A](t: CountTable[A], key: A): bool =
   ## the `in` operator.
   return hasKey[A](t, key)
 
-proc getOrDefault*[A](t: CountTable[A], key: A; default: int = 0): int =
+proc getOrDefault*[A](t: CountTable[A], key: A; def: int = 0): int =
   ## Retrieves the value at `t[key]` if `key` is in `t`. Otherwise, the
-  ## integer value of `default` is returned.
+  ## integer value of `def` is returned.
   ##
   ## See also:
   ## * `[] proc<#[],CountTable[A],A>`_ for retrieving a value of a key
   ## * `hasKey proc<#hasKey,CountTable[A],A>`_ for checking if a key
   ##   is in the table
-  ctget(t, key, default)
+  ctget(t, key, def)
 
 proc del*[A](t: var CountTable[A], key: A) {.since: (1, 1).} =
   ## Deletes `key` from table `t`. Does nothing if the key does not exist.
@@ -2772,15 +2770,15 @@ proc contains*[A](t: CountTableRef[A], key: A): bool =
   ## the `in` operator.
   return hasKey[A](t, key)
 
-proc getOrDefault*[A](t: CountTableRef[A], key: A, default: int): int =
+proc getOrDefault*[A](t: CountTableRef[A], key: A, def: int): int =
   ## Retrieves the value at `t[key]` if `key` is in `t`. Otherwise, the
-  ## integer value of `default` is returned.
+  ## integer value of `def` is returned.
   ##
   ## See also:
   ## * `[] proc<#[],CountTableRef[A],A>`_ for retrieving a value of a key
   ## * `hasKey proc<#hasKey,CountTableRef[A],A>`_ for checking if a key
   ##   is in the table
-  result = t[].getOrDefault(key, default)
+  result = t[].getOrDefault(key, def)
 
 proc len*[A](t: CountTableRef[A]): int =
   ## Returns the number of keys in `t`.

testament/important_packages.nim

@@ -149,7 +149,7 @@ pkg "polypbren"
 pkg "presto"
 pkg "prologue", "nimble tcompile"
 # remove fork after https://github.com/PMunch/combparser/pull/7 is merged:
-pkg "protobuf", "nimble install -y https://github.com/metagn/combparser@#HEAD; nim c -o:protobuff -r src/protobuf.nim"
+pkg "protobuf", "nimble uninstall -i -y combparser; nimble install -y https://github.com/metagn/combparser@#HEAD; nimble install --depsOnly -y; nim c -o:protobuff -r src/protobuf.nim"
 pkg "rbtree"
 pkg "react", "nimble example"
 pkg "regex", "nim c src/regex"

tests/stdlib/ttables.nim

@@ -314,3 +314,18 @@ block countTableWithoutInit:
   d.inc("f")
   merge(d, e)
   doAssert d["f"] == 7
+
+block: # issue #23587
+  type
+    A = proc ()
+
+  proc main =
+    let repo = initTable[uint32, A]()
+
+    let c1 = repo.getOrDefault(uint32(1), nil)
+    doAssert c1.isNil
+
+    let c2 = repo.getOrDefault(uint32(1), A(nil))
+    doAssert c2.isNil
+
+  main()