Reapply "[Feature #6012] Extend `source_location` for end position

* This reverts commit 065c48cdf11a1c4cece84db44ed8624d294f8fd5.
* This functionality is very valuable and has already taken 14 years
  to agree on the API.
* Let's just document it's byte columns (in the next commit).
* See https://bugs.ruby-lang.org/issues/21783#note-9

3 files changed, 55 insertions, 30 deletions

diff --git a/spec/ruby/core/method/source_location_spec.rb b/spec/ruby/core/method/source_location_spec.rb
index c5b296f6e2..1b175ebaba 100644
--- a/spec/ruby/core/method/source_location_spec.rb
+++ b/spec/ruby/core/method/source_location_spec.rb
@@ -11,23 +11,23 @@ describe "Method#source_location" do
   end
 
   it "sets the first value to the path of the file in which the method was defined" do
-    file = @method.source_location.first
+    file = @method.source_location[0]
     file.should be_an_instance_of(String)
     file.should == File.realpath('fixtures/classes.rb', __dir__)
   end
 
   it "sets the last value to an Integer representing the line on which the method was defined" do
-    line = @method.source_location.last
+    line = @method.source_location[1]
     line.should be_an_instance_of(Integer)
     line.should == 5
   end
 
   it "returns the last place the method was defined" do
-    MethodSpecs::SourceLocation.method(:redefined).source_location.last.should == 13
+    MethodSpecs::SourceLocation.method(:redefined).source_location[1].should == 13
   end
 
   it "returns the location of the original method even if it was aliased" do
-    MethodSpecs::SourceLocation.new.method(:aka).source_location.last.should == 17
+    MethodSpecs::SourceLocation.new.method(:aka).source_location[1].should == 17
   end
 
   it "works for methods defined with a block" do
@@ -108,7 +108,13 @@ describe "Method#source_location" do
     c = Class.new do
       eval('def self.m; end', nil, "foo", 100)
     end
-    c.method(:m).source_location.should == ["foo", 100]
+    location = c.method(:m).source_location
+    ruby_version_is(""..."4.0") do
+      location.should == ["foo", 100]
+    end
+    ruby_version_is("4.0") do
+      location.should == ["foo", 100, 0, 100, 15]
+    end
   end
 
   describe "for a Method generated by respond_to_missing?" do
diff --git a/spec/ruby/core/proc/source_location_spec.rb b/spec/ruby/core/proc/source_location_spec.rb
index a8b99287d5..69b4e2fd82 100644
--- a/spec/ruby/core/proc/source_location_spec.rb
+++ b/spec/ruby/core/proc/source_location_spec.rb
@@ -17,57 +17,64 @@ describe "Proc#source_location" do
   end
 
   it "sets the first value to the path of the file in which the proc was defined" do
-    file = @proc.source_location.first
+    file = @proc.source_location[0]
     file.should be_an_instance_of(String)
     file.should == File.realpath('fixtures/source_location.rb', __dir__)
 
-    file = @proc_new.source_location.first
+    file = @proc_new.source_location[0]
     file.should be_an_instance_of(String)
     file.should == File.realpath('fixtures/source_location.rb', __dir__)
 
-    file = @lambda.source_location.first
+    file = @lambda.source_location[0]
     file.should be_an_instance_of(String)
     file.should == File.realpath('fixtures/source_location.rb', __dir__)
 
-    file = @method.source_location.first
+    file = @method.source_location[0]
     file.should be_an_instance_of(String)
     file.should == File.realpath('fixtures/source_location.rb', __dir__)
   end
 
-  it "sets the last value to an Integer representing the line on which the proc was defined" do
-    line = @proc.source_location.last
+  it "sets the second value to an Integer representing the line on which the proc was defined" do
+    line = @proc.source_location[1]
     line.should be_an_instance_of(Integer)
     line.should == 4
 
-    line = @proc_new.source_location.last
+    line = @proc_new.source_location[1]
     line.should be_an_instance_of(Integer)
     line.should == 12
 
-    line = @lambda.source_location.last
+    line = @lambda.source_location[1]
     line.should be_an_instance_of(Integer)
     line.should == 8
 
-    line = @method.source_location.last
+    line = @method.source_location[1]
     line.should be_an_instance_of(Integer)
     line.should == 15
   end
 
   it "works even if the proc was created on the same line" do
-    proc { true }.source_location.should == [__FILE__, __LINE__]
-    Proc.new { true }.source_location.should == [__FILE__, __LINE__]
-    -> { true }.source_location.should == [__FILE__, __LINE__]
+    ruby_version_is(""..."4.0") do
+      proc { true }.source_location.should == [__FILE__, __LINE__]
+      Proc.new { true }.source_location.should == [__FILE__, __LINE__]
+      -> { true }.source_location.should == [__FILE__, __LINE__]
+    end
+    ruby_version_is("4.0") do
+      proc { true }.source_location.should == [__FILE__, __LINE__, 11, __LINE__, 19]
+      Proc.new { true }.source_location.should == [__FILE__, __LINE__, 15, __LINE__, 23]
+      -> { true }.source_location.should == [__FILE__, __LINE__, 8, __LINE__, 17]
+    end
   end
 
   it "returns the first line of a multi-line proc (i.e. the line containing 'proc do')" do
-    ProcSpecs::SourceLocation.my_multiline_proc.source_location.last.should == 20
-    ProcSpecs::SourceLocation.my_multiline_proc_new.source_location.last.should == 34
-    ProcSpecs::SourceLocation.my_multiline_lambda.source_location.last.should == 27
+    ProcSpecs::SourceLocation.my_multiline_proc.source_location[1].should == 20
+    ProcSpecs::SourceLocation.my_multiline_proc_new.source_location[1].should == 34
+    ProcSpecs::SourceLocation.my_multiline_lambda.source_location[1].should == 27
   end
 
   it "returns the location of the proc's body; not necessarily the proc itself" do
-    ProcSpecs::SourceLocation.my_detached_proc.source_location.last.should == 41
-    ProcSpecs::SourceLocation.my_detached_proc_new.source_location.last.should == 51
-    ProcSpecs::SourceLocation.my_detached_lambda.source_location.last.should == 46
+    ProcSpecs::SourceLocation.my_detached_proc.source_location[1].should == 41
+    ProcSpecs::SourceLocation.my_detached_proc_new.source_location[1].should == 51
+    ProcSpecs::SourceLocation.my_detached_lambda.source_location[1].should == 46
   end
 
   it "returns the same value for a proc-ified method as the method reports" do
@@ -86,6 +93,12 @@ describe "Proc#source_location" do
 
   it "works for eval with a given line" do
     proc = eval('-> {}', nil, "foo", 100)
-    proc.source_location.should == ["foo", 100]
+    location = proc.source_location
+    ruby_version_is(""..."4.0") do
+      location.should == ["foo", 100]
+    end
+    ruby_version_is("4.0") do
+      location.should == ["foo", 100, 2, 100, 5]
+    end
   end
 end
diff --git a/spec/ruby/core/unboundmethod/source_location_spec.rb b/spec/ruby/core/unboundmethod/source_location_spec.rb
index 5c2f14362c..85078ff34e 100644
--- a/spec/ruby/core/unboundmethod/source_location_spec.rb
+++ b/spec/ruby/core/unboundmethod/source_location_spec.rb
@@ -7,23 +7,23 @@ describe "UnboundMethod#source_location" do
   end
 
   it "sets the first value to the path of the file in which the method was defined" do
-    file = @method.source_location.first
+    file = @method.source_location[0]
     file.should be_an_instance_of(String)
     file.should == File.realpath('fixtures/classes.rb', __dir__)
   end
 
-  it "sets the last value to an Integer representing the line on which the method was defined" do
-    line = @method.source_location.last
+  it "sets the second value to an Integer representing the line on which the method was defined" do
+    line = @method.source_location[1]
     line.should be_an_instance_of(Integer)
     line.should == 5
   end
 
   it "returns the last place the method was defined" do
-    UnboundMethodSpecs::SourceLocation.method(:redefined).unbind.source_location.last.should == 13
+    UnboundMethodSpecs::SourceLocation.method(:redefined).unbind.source_location[1].should == 13
   end
 
   it "returns the location of the original method even if it was aliased" do
-    UnboundMethodSpecs::SourceLocation.instance_method(:aka).source_location.last.should == 17
+    UnboundMethodSpecs::SourceLocation.instance_method(:aka).source_location[1].should == 17
   end
 
   it "works for define_method methods" do
@@ -54,6 +54,12 @@ describe "UnboundMethod#source_location" do
     c = Class.new do
       eval('def m; end', nil, "foo", 100)
     end
-    c.instance_method(:m).source_location.should == ["foo", 100]
+    location = c.instance_method(:m).source_location
+    ruby_version_is(""..."4.0") do
+      location.should == ["foo", 100]
+    end
+    ruby_version_is("4.0") do
+      location.should == ["foo", 100, 0, 100, 10]
+    end
   end
 end