Fix Indexable.range_to_index_and_count to not raise IndexError (#10191)

* Fix Indexable.range_to_index_and_count to not raise IndexError

* Let Indexable.range_to_index_and_count return nil

spec/std/string_spec.cr

@@ -182,6 +182,8 @@ describe "String" do
     it "gets with range" do
       "hello"[1..2]?.should eq "el"
       "hello"[6..-1]?.should be_nil
+      "hello"[-6..-1]?.should be_nil
+      "hello"[-6..]?.should be_nil
     end
 
     it "gets with start and count" do

src/array.cr

@@ -504,7 +504,7 @@ class Array(T)
   # a # => [1, 2, 6]
   # ```
   def []=(range : Range, value : T)
-    self[*Indexable.range_to_index_and_count(range, size)] = value
+    self[*Indexable.range_to_index_and_count(range, size) || raise IndexError.new] = value
   end
 
   # Replaces a subrange with the elements of the given array.
@@ -576,7 +576,7 @@ class Array(T)
   # a # => [1, 2, 6, 7, 8, 9, 10]
   # ```
   def []=(range : Range, values : Array(T))
-    self[*Indexable.range_to_index_and_count(range, size)] = values
+    self[*Indexable.range_to_index_and_count(range, size) || raise IndexError.new] = values
   end
 
   # Returns all elements that are within the given range.
@@ -597,7 +597,7 @@ class Array(T)
   # a[2..]     # => ["c", "d", "e"]
   # ```
   def [](range : Range)
-    self[*Indexable.range_to_index_and_count(range, size)]
+    self[*Indexable.range_to_index_and_count(range, size) || raise IndexError.new]
   end
 
   # Like `#[Range]`, but returns `nil` if the range's start is out of range.
@@ -608,7 +608,7 @@ class Array(T)
   # a[6..]?   # => nil
   # ```
   def []?(range : Range)
-    self[*Indexable.range_to_index_and_count(range, size)]?
+    self[*Indexable.range_to_index_and_count(range, size) || return nil]?
   end
 
   # Returns count or less (if there aren't enough) elements starting at the
@@ -813,7 +813,7 @@ class Array(T)
   # a.delete_at(99..100) # raises IndexError
   # ```
   def delete_at(range : Range)
-    index, count = Indexable.range_to_index_and_count(range, self.size)
+    index, count = Indexable.range_to_index_and_count(range, self.size) || raise IndexError.new
     delete_at(index, count)
   end
 
@@ -932,7 +932,7 @@ class Array(T)
   # a.fill(2..3) { |i| i * i } # => [1, 2, 4, 9, 5, 6]
   # ```
   def fill(range : Range)
-    fill(*Indexable.range_to_index_and_count(range, size)) do |i|
+    fill(*Indexable.range_to_index_and_count(range, size) || raise IndexError.new) do |i|
       yield i
     end
   end
@@ -1020,7 +1020,7 @@ class Array(T)
   def fill(value : T, range : Range)
     {% if Int::Primitive.union_types.includes?(T) || Float::Primitive.union_types.includes?(T) %}
       if value == 0
-        fill(value, *Indexable.range_to_index_and_count(range, size))
+        fill(value, *Indexable.range_to_index_and_count(range, size) || raise IndexError.new)
 
         self
       else

src/bit_array.cr

@@ -85,7 +85,7 @@ struct BitArray
   # ba[-2...-1] # => BitArray[0]
   # ```
   def [](range : Range)
-    self[*Indexable.range_to_index_and_count(range, size)]
+    self[*Indexable.range_to_index_and_count(range, size) || raise IndexError.new]
   end
 
   # Returns count or less (if there aren't enough) elements starting at the

src/indexable.cr

@@ -245,7 +245,7 @@ module Indexable(T)
   # b -- c -- d --
   # ```
   def each(*, within range : Range)
-    start, count = Indexable.range_to_index_and_count(range, size)
+    start, count = Indexable.range_to_index_and_count(range, size) || raise IndexError.new
     each(start: start, count: count) { |element| yield element }
   end
 
@@ -600,7 +600,9 @@ module Indexable(T)
       start_index = 0
     else
       start_index += collection_size if start_index < 0
-      raise IndexError.new if start_index < 0
+      if start_index < 0
+        return nil
+      end
     end
 
     end_index = range.end

src/regex/match_data.cr

@@ -204,12 +204,12 @@ class Regex
 
     # Returns all matches that are within the given range.
     def [](range : Range)
-      self[*Indexable.range_to_index_and_count(range, size)]
+      self[*Indexable.range_to_index_and_count(range, size) || raise IndexError.new]
     end
 
     # Like `#[Range]`, but returns `nil` if the range's start is out of range.
     def []?(range : Range)
-      self[*Indexable.range_to_index_and_count(range, size)]?
+      self[*Indexable.range_to_index_and_count(range, size) || raise IndexError.new]?
     end
 
     # Returns count or less (if there aren't enough) matches starting at the

src/slice.cr

@@ -245,7 +245,7 @@ struct Slice(T)
   # slice[1..33]? # => nil
   # ```
   def []?(range : Range)
-    start, count = Indexable.range_to_index_and_count(range, size)
+    start, count = Indexable.range_to_index_and_count(range, size) || raise IndexError.new
     self[start, count]?
   end
 
@@ -265,7 +265,7 @@ struct Slice(T)
   # slice[1..33] # raises IndexError
   # ```
   def [](range : Range)
-    start, count = Indexable.range_to_index_and_count(range, size)
+    start, count = Indexable.range_to_index_and_count(range, size) || raise IndexError.new
     self[start, count]
   end
 

src/string.cr

@@ -760,7 +760,7 @@ class String
   # "hello"[6..7]   # raises IndexError
   # ```
   def [](range : Range)
-    self[*Indexable.range_to_index_and_count(range, size)]
+    self[*Indexable.range_to_index_and_count(range, size) || raise IndexError.new]
   end
 
   # Like `#[Range]`, but returns `nil` if the range's start is out of bounds.
@@ -770,7 +770,7 @@ class String
   # "hello"[6..]?  # => nil
   # ```
   def []?(range : Range)
-    self[*Indexable.range_to_index_and_count(range, size)]?
+    self[*Indexable.range_to_index_and_count(range, size) || return nil]?
   end
 
   # Returns a substring starting from the *start* character of size *count*.
@@ -902,7 +902,7 @@ class String
   #
   # Raises `IndexError` if any index is outside the bounds of this string.
   def delete_at(range : Range)
-    delete_at(*Indexable.range_to_index_and_count(range, size))
+    delete_at(*Indexable.range_to_index_and_count(range, size) || raise IndexError.new)
   end
 
   # Returns a new string that results from deleting the character
@@ -2303,7 +2303,7 @@ class String
   end
 
   private def sub_range(range, replacement)
-    from, size = Indexable.range_to_index_and_count(range, self.size)
+    from, size = Indexable.range_to_index_and_count(range, self.size) || raise IndexError.new
 
     from_index = char_index_to_byte_index(from)
     raise IndexError.new unless from_index