Check redundant clauses for definitions (#15124)

Author: josevalim

lib/elixir/lib/calendar/date_range.ex

@@ -59,11 +59,20 @@ defmodule Date.Range do
     end
 
     # TODO: Remove me on v2.0
-    def member?(
-          %{__struct__: Date.Range, first_in_iso_days: first_days, last_in_iso_days: last_days} =
-            date_range,
-          date
-        ) do
+    member? =
+      quote generated: true do
+        member?(
+          %{
+            __struct__: Date.Range,
+            first_in_iso_days: var!(first_days),
+            last_in_iso_days: var!(last_days)
+          } =
+            var!(date_range),
+          var!(date)
+        )
+      end
+
+    def unquote(member?) do
       step = if first_days <= last_days, do: 1, else: -1
       member?(Map.put(date_range, :step, step), date)
     end
@@ -218,11 +227,11 @@ defmodule Date.Range do
   defimpl Inspect do
     import Kernel, except: [inspect: 2]
 
-    def inspect(%Date.Range{first: first, last: last, step: 1}, _) do
+    def inspect(%Date.Range{first: first, last: last, step: 1}, %Inspect.Opts{}) do
       "Date.range(" <> inspect(first) <> ", " <> inspect(last) <> ")"
     end
 
-    def inspect(%Date.Range{first: first, last: last, step: step}, _) do
+    def inspect(%Date.Range{first: first, last: last, step: step}, %Inspect.Opts{}) do
       "Date.range(" <> inspect(first) <> ", " <> inspect(last) <> ", #{step})"
     end
 

lib/elixir/lib/enum.ex

@@ -5168,7 +5168,16 @@ defimpl Enumerable, for: Range do
   end
 
   # TODO: Remove me on v2.0
-  def reduce(%{__struct__: Range, first: first, last: last} = range, acc, fun) do
+  reduce =
+    quote generated: true do
+      reduce(
+        %{__struct__: Range, first: var!(first), last: var!(last)} = var!(range),
+        var!(acc),
+        var!(fun)
+      )
+    end
+
+  def unquote(reduce) do
     step = if first <= last, do: 1, else: -1
     reduce(Map.put(range, :step, step), acc, fun)
   end
@@ -5191,12 +5200,12 @@ defimpl Enumerable, for: Range do
     {:done, acc}
   end
 
-  def member?(first..last//step, value) when is_integer(value) do
-    if step > 0 do
-      {:ok, first <= value and value <= last and rem(value - first, step) == 0}
-    else
-      {:ok, last <= value and value <= first and rem(value - first, step) == 0}
-    end
+  def member?(first..last//step, value) when is_integer(value) and step > 0 do
+    {:ok, first <= value and value <= last and rem(value - first, step) == 0}
+  end
+
+  def member?(first..last//step, value) when is_integer(value) and step < 0 do
+    {:ok, last <= value and value <= first and rem(value - first, step) == 0}
   end
 
   # TODO: Remove me on v2.0
@@ -5219,7 +5228,13 @@ defimpl Enumerable, for: Range do
   end
 
   # TODO: Remove me on v2.0
-  def slice(%{__struct__: Range, first: first, last: last} = range) do
+
+  slice =
+    quote generated: true do
+      slice(%{__struct__: Range, first: var!(first), last: var!(last)} = var!(range))
+    end
+
+  def unquote(slice) do
     step = if first <= last, do: 1, else: -1
     slice(Map.put(range, :step, step))
   end

lib/elixir/lib/inspect.ex

@@ -696,7 +696,15 @@ defimpl Inspect, for: Range do
   end
 
   # TODO: Remove me on v2.0
-  def inspect(%{__struct__: Range, first: first, last: last} = range, opts) do
+  inspect =
+    quote generated: true do
+      inspect(
+        %{__struct__: Range, first: var!(first), last: var!(last)} = var!(range),
+        var!(opts)
+      )
+    end
+
+  def unquote(inspect) do
     step = if first <= last, do: 1, else: -1
     inspect(Map.put(range, :step, step), opts)
   end

lib/elixir/lib/module/types.ex

@@ -319,16 +319,17 @@ defmodule Module.Types do
   defp local_handler(mode, fun_arity, kind, meta, clauses, expected, stack, context) do
     {fun, _arity} = fun_arity
     stack = stack |> fresh_stack(mode, fun_arity) |> with_file_meta(meta)
+    base_info = {:def, kind, fun, expected}
 
-    {_, _, mapping, clauses_types, clauses_context} =
-      Enum.reduce(clauses, {0, 0, [], [], context}, fn
-        {meta, args, guards, body}, {index, total, mapping, inferred, context} ->
-          context = fresh_context(context)
-          info = {:def, kind, fun, args, guards, expected}
+    {_, _, _, mapping, clauses_types, clauses_context} =
+      Enum.reduce(clauses, {0, 0, [], [], [], context}, fn
+        {meta, args, guards, body}, {index, total, previous, mapping, inferred, acc_context} ->
+          fresh_context = fresh_context(acc_context)
+          info = {base_info, args, guards}
 
           try do
-            {trees, _precise?, context} =
-              Pattern.of_head(args, guards, expected, info, meta, stack, context)
+            {trees, previous, context} =
+              Pattern.of_head(args, guards, expected, previous, info, meta, stack, fresh_context)
 
             {return_type, context} =
               Expr.of_expr(body, Descr.term(), body, stack, context)
@@ -339,9 +340,9 @@ defmodule Module.Types do
               add_inferred(inferred, args_types, return_type, total - 1, [])
 
             if type_index == -1 do
-              {index + 1, total + 1, [{index, total} | mapping], inferred, context}
+              {index + 1, total + 1, previous, [{index, total} | mapping], inferred, context}
             else
-              {index + 1, total, [{index, type_index} | mapping], inferred, context}
+              {index + 1, total, previous, [{index, type_index} | mapping], inferred, context}
             end
           rescue
             e ->

lib/elixir/lib/module/types/expr.ex

@@ -719,62 +719,24 @@ defmodule Module.Types.Expr do
   defp dynamic_unless_static({_, _} = output, %{mode: :static}), do: output
   defp dynamic_unless_static({type, context}, %{mode: _}), do: {dynamic(type), context}
 
-  defp of_clauses(clauses, domain, expected, clause_info, stack, context, acc) do
+  defp of_clauses(clauses, domain, expected, base_info, stack, context, acc) do
     fun = fn _args_types, result, _context, acc -> union(result, acc) end
-    of_clauses_fun(clauses, domain, expected, clause_info, stack, context, acc, fun)
+    of_clauses_fun(clauses, domain, expected, base_info, stack, context, acc, fun)
   end
 
-  defp of_clauses_fun(clauses, domain, expected, clause_info, stack, original, acc, fun) do
+  defp of_clauses_fun(clauses, domain, expected, base_info, stack, original, acc, fun) do
     %{failed: failed?} = original
 
     {result, _previous, context} =
       Enum.reduce(clauses, {acc, [], original}, fn
-        {:->, meta, [head, body]} = clause, {acc, previous, context} ->
+        {:->, meta, [head, body]}, {acc, previous, context} ->
           {failed?, context} = reset_failed(context, failed?)
           {patterns, guards} = extract_head(head)
-          info = {clause_info, head, previous}
+          info = {base_info, head}
 
-          {trees, precise?, context} =
+          {trees, previous, context} =
             Pattern.of_head(patterns, guards, domain, previous, info, meta, stack, context)
 
-          # It failed, let's try to detect if it was due a previous or current clause.
-          # The current clause will be easier to understand, so we prefer that
-          {trees, precise?, context} =
-            if context.failed and previous != [] do
-              info = {clause_info, head, []}
-
-              case Pattern.of_head(patterns, guards, domain, info, meta, stack, context) do
-                {_, _, %{failed: true}} = result -> result
-                _ -> {trees, precise?, context}
-              end
-            else
-              {trees, precise?, context}
-            end
-
-          {previous, context} =
-            if context.failed do
-              {previous, context}
-            else
-              args_types =
-                Enum.map(trees, fn {tree, _, _} ->
-                  tree
-                  |> Pattern.of_pattern_tree(stack, context)
-                  |> upper_bound()
-                end)
-
-              cond do
-                stack.mode != :infer and previous != [] and
-                    Pattern.args_subtype?(args_types, previous) ->
-                  {previous, Pattern.redundant_warn(clause, previous, stack, context)}
-
-                precise? ->
-                  {[args_types | previous], context}
-
-                true ->
-                  {previous, context}
-              end
-            end
-
           {result, context} = of_expr(body, expected, body, stack, context)
 
           {fun.(trees, result, context, acc), previous,

lib/elixir/lib/module/types/of.ex

@@ -187,6 +187,13 @@ defmodule Module.Types.Of do
       }),
       do: %{context | subpatterns: subpatterns, vars: vars, conditional_vars: conditional_vars}
 
+  @doc """
+  Returns true if all entries have the same conditional vars.
+  """
+  def all_same_conditional_vars?([{_, cond} | tail]) do
+    Enum.all?(tail, fn {_, tail_cond} -> cond == tail_cond end)
+  end
+
   @doc """
   Executes the args with acc using conditional variables.
   """