diff --git a/spec/ameba/rule/layout/line_length_spec.cr b/spec/ameba/rule/layout/line_length_spec.cr
index 10392789..71a1b1ea 100644
--- a/spec/ameba/rule/layout/line_length_spec.cr
+++ b/spec/ameba/rule/layout/line_length_spec.cr
@@ -6,13 +6,15 @@ module Ameba::Rule::Layout
 
   describe LineLength do
     it "passes if all lines are shorter than MaxLength symbols" do
-      source = Source.new "short line"
-      subject.catch(source).should be_valid
+      expect_no_issues subject, <<-CRYSTAL
+        short line
+        CRYSTAL
     end
 
     it "passes if line consists of MaxLength symbols" do
-      source = Source.new "*" * subject.max_length
-      subject.catch(source).should be_valid
+      expect_no_issues subject, <<-CRYSTAL
+        #{"*" * subject.max_length}
+        CRYSTAL
     end
 
     it "fails if there is at least one line longer than MaxLength symbols" do
@@ -33,10 +35,10 @@ module Ameba::Rule::Layout
 
     context "properties" do
       it "allows to configure max length of the line" do
-        source = Source.new long_line
         rule = LineLength.new
         rule.max_length = long_line.size
-        rule.catch(source).should be_valid
+
+        expect_no_issues rule, long_line
       end
     end
   end
diff --git a/spec/ameba/rule/lint/ambiguous_assignment_spec.cr b/spec/ameba/rule/lint/ambiguous_assignment_spec.cr
index 153f1796..a808df40 100644
--- a/spec/ameba/rule/lint/ambiguous_assignment_spec.cr
+++ b/spec/ameba/rule/lint/ambiguous_assignment_spec.cr
@@ -6,163 +6,115 @@ module Ameba::Rule::Lint
 
     context "when using `-`" do
       it "registers an offense with `x`" do
-        source = Source.new("x =- y", "source.cr")
-        subject.catch(source).should_not be_valid
-        source.issues.size.should eq 1
-
-        issue = source.issues.first
-        issue.message.should eq "Suspicious assignment detected. Did you mean `-=`?"
-        issue.location.to_s.should eq "source.cr:1:3"
-        issue.end_location.to_s.should eq "source.cr:1:4"
+        expect_issue subject, <<-CRYSTAL
+          x =- y
+          # ^^ error: Suspicious assignment detected. Did you mean `-=`?
+          CRYSTAL
       end
 
       it "registers an offense with `@x`" do
-        source = Source.new("@x =- y", "source.cr")
-        subject.catch(source).should_not be_valid
-        source.issues.size.should eq 1
-
-        issue = source.issues.first
-        issue.message.should eq "Suspicious assignment detected. Did you mean `-=`?"
-        issue.location.to_s.should eq "source.cr:1:4"
-        issue.end_location.to_s.should eq "source.cr:1:5"
+        expect_issue subject, <<-CRYSTAL
+          @x =- y
+           # ^^ error: Suspicious assignment detected. Did you mean `-=`?
+          CRYSTAL
       end
 
       it "registers an offense with `@@x`" do
-        source = Source.new("@@x =- y", "source.cr")
-        subject.catch(source).should_not be_valid
-        source.issues.size.should eq 1
-
-        issue = source.issues.first
-        issue.message.should eq "Suspicious assignment detected. Did you mean `-=`?"
-        issue.location.to_s.should eq "source.cr:1:5"
-        issue.end_location.to_s.should eq "source.cr:1:6"
+        expect_issue subject, <<-CRYSTAL
+          @@x =- y
+            # ^^ error: Suspicious assignment detected. Did you mean `-=`?
+          CRYSTAL
       end
 
       it "registers an offense with `X`" do
-        source = Source.new("X =- y", "source.cr")
-        subject.catch(source).should_not be_valid
-        source.issues.size.should eq 1
-
-        issue = source.issues.first
-        issue.message.should eq "Suspicious assignment detected. Did you mean `-=`?"
-        issue.location.to_s.should eq "source.cr:1:3"
-        issue.end_location.to_s.should eq "source.cr:1:4"
+        expect_issue subject, <<-CRYSTAL
+          X =- y
+          # ^^ error: Suspicious assignment detected. Did you mean `-=`?
+          CRYSTAL
       end
 
       it "does not register an offense when no mistype assignments" do
-        subject.catch(Source.new(<<-CRYSTAL)).should be_valid
+        expect_no_issues subject, <<-CRYSTAL
           x = 1
           x -= y
           x = -y
-        CRYSTAL
+          CRYSTAL
       end
     end
 
     context "when using `+`" do
       it "registers an offense with `x`" do
-        source = Source.new("x =+ y", "source.cr")
-        subject.catch(source).should_not be_valid
-        source.issues.size.should eq 1
-
-        issue = source.issues.first
-        issue.message.should eq "Suspicious assignment detected. Did you mean `+=`?"
-        issue.location.to_s.should eq "source.cr:1:3"
-        issue.end_location.to_s.should eq "source.cr:1:4"
+        expect_issue subject, <<-CRYSTAL
+          x =+ y
+          # ^^ error: Suspicious assignment detected. Did you mean `+=`?
+          CRYSTAL
       end
 
       it "registers an offense with `@x`" do
-        source = Source.new("@x =+ y", "source.cr")
-        subject.catch(source).should_not be_valid
-        source.issues.size.should eq 1
-
-        issue = source.issues.first
-        issue.message.should eq "Suspicious assignment detected. Did you mean `+=`?"
-        issue.location.to_s.should eq "source.cr:1:4"
-        issue.end_location.to_s.should eq "source.cr:1:5"
+        expect_issue subject, <<-CRYSTAL
+          @x =+ y
+           # ^^ error: Suspicious assignment detected. Did you mean `+=`?
+          CRYSTAL
       end
 
       it "registers an offense with `@@x`" do
-        source = Source.new("@@x =+ y", "source.cr")
-        subject.catch(source).should_not be_valid
-        source.issues.size.should eq 1
-
-        issue = source.issues.first
-        issue.message.should eq "Suspicious assignment detected. Did you mean `+=`?"
-        issue.location.to_s.should eq "source.cr:1:5"
-        issue.end_location.to_s.should eq "source.cr:1:6"
+        expect_issue subject, <<-CRYSTAL
+          @@x =+ y
+            # ^^ error: Suspicious assignment detected. Did you mean `+=`?
+          CRYSTAL
       end
 
       it "registers an offense with `X`" do
-        source = Source.new("X =+ y", "source.cr")
-        subject.catch(source).should_not be_valid
-        source.issues.size.should eq 1
-
-        issue = source.issues.first
-        issue.message.should eq "Suspicious assignment detected. Did you mean `+=`?"
-        issue.location.to_s.should eq "source.cr:1:3"
-        issue.end_location.to_s.should eq "source.cr:1:4"
+        expect_issue subject, <<-CRYSTAL
+          X =+ y
+          # ^^ error: Suspicious assignment detected. Did you mean `+=`?
+          CRYSTAL
       end
 
       it "does not register an offense when no mistype assignments" do
-        subject.catch(Source.new(<<-CRYSTAL)).should be_valid
+        expect_no_issues subject, <<-CRYSTAL
           x = 1
           x += y
           x = +y
-        CRYSTAL
+          CRYSTAL
       end
     end
 
     context "when using `!`" do
       it "registers an offense with `x`" do
-        source = Source.new("x =! y", "source.cr")
-        subject.catch(source).should_not be_valid
-        source.issues.size.should eq 1
-
-        issue = source.issues.first
-        issue.message.should eq "Suspicious assignment detected. Did you mean `!=`?"
-        issue.location.to_s.should eq "source.cr:1:3"
-        issue.end_location.to_s.should eq "source.cr:1:4"
+        expect_issue subject, <<-CRYSTAL
+          x =! y
+          # ^^ error: Suspicious assignment detected. Did you mean `!=`?
+          CRYSTAL
       end
 
       it "registers an offense with `@x`" do
-        source = Source.new("@x =! y", "source.cr")
-        subject.catch(source).should_not be_valid
-        source.issues.size.should eq 1
-
-        issue = source.issues.first
-        issue.message.should eq "Suspicious assignment detected. Did you mean `!=`?"
-        issue.location.to_s.should eq "source.cr:1:4"
-        issue.end_location.to_s.should eq "source.cr:1:5"
+        expect_issue subject, <<-CRYSTAL
+          @x =! y
+           # ^^ error: Suspicious assignment detected. Did you mean `!=`?
+          CRYSTAL
       end
 
       it "registers an offense with `@@x`" do
-        source = Source.new("@@x =! y", "source.cr")
-        subject.catch(source).should_not be_valid
-        source.issues.size.should eq 1
-
-        issue = source.issues.first
-        issue.message.should eq "Suspicious assignment detected. Did you mean `!=`?"
-        issue.location.to_s.should eq "source.cr:1:5"
-        issue.end_location.to_s.should eq "source.cr:1:6"
+        expect_issue subject, <<-CRYSTAL
+          @@x =! y
+            # ^^ error: Suspicious assignment detected. Did you mean `!=`?
+          CRYSTAL
       end
 
       it "registers an offense with `X`" do
-        source = Source.new("X =! y", "source.cr")
-        subject.catch(source).should_not be_valid
-        source.issues.size.should eq 1
-
-        issue = source.issues.first
-        issue.message.should eq "Suspicious assignment detected. Did you mean `!=`?"
-        issue.location.to_s.should eq "source.cr:1:3"
-        issue.end_location.to_s.should eq "source.cr:1:4"
+        expect_issue subject, <<-CRYSTAL
+          X =! y
+          # ^^ error: Suspicious assignment detected. Did you mean `!=`?
+          CRYSTAL
       end
 
       it "does not register an offense when no mistype assignments" do
-        subject.catch(Source.new(<<-CRYSTAL)).should be_valid
+        expect_no_issues subject, <<-CRYSTAL
           x = false
           x != y
           x = !y
-        CRYSTAL
+          CRYSTAL
       end
     end
   end
diff --git a/spec/ameba/rule/lint/bad_directive_spec.cr b/spec/ameba/rule/lint/bad_directive_spec.cr
index 5667982d..765a83ec 100644
--- a/spec/ameba/rule/lint/bad_directive_spec.cr
+++ b/spec/ameba/rule/lint/bad_directive_spec.cr
@@ -5,62 +5,42 @@ module Ameba::Rule::Lint
     subject = BadDirective.new
 
     it "does not report if rule is correct" do
-      s = Source.new %(
+      expect_no_issues subject, <<-CRYSTAL
         # ameba:disable Lint/BadDirective
-      )
-      subject.catch(s).should be_valid
+        CRYSTAL
     end
 
     it "reports if there is incorrect action" do
-      s = Source.new %(
+      expect_issue subject, <<-CRYSTAL
         # ameba:foo Lint/BadDirective
-      ), "source.cr"
-      subject.catch(s).should_not be_valid
-      s.issues.size.should eq 1
-
-      issue = s.issues.first
-      issue.message.should eq(
-        "Bad action in comment directive: 'foo'. Possible values: disable, enable"
-      )
-      issue.location.to_s.should eq "source.cr:1:1"
-      issue.end_location.to_s.should eq ""
+        # ^{} error: Bad action in comment directive: 'foo'. Possible values: disable, enable
+        CRYSTAL
     end
 
     it "reports if there are incorrect rule names" do
-      s = Source.new %(
+      expect_issue subject, <<-CRYSTAL
         # ameba:enable BadRule1, BadRule2
-      ), "source.cr"
-      subject.catch(s).should_not be_valid
-      s.issues.size.should eq 1
-
-      issue = s.issues.first
-      issue.message.should eq(
-        "Such rules do not exist: BadRule1, BadRule2"
-      )
-      issue.location.to_s.should eq "source.cr:1:1"
-      issue.end_location.to_s.should eq ""
+        # ^{} error: Such rules do not exist: BadRule1, BadRule2
+        CRYSTAL
     end
 
     it "does not report if there no action and rules at all" do
-      s = Source.new %(
+      expect_no_issues subject, <<-CRYSTAL
         # ameba:
-      )
-      subject.catch(s).should be_valid
+        CRYSTAL
     end
 
     it "does not report if there are no rules" do
-      s = Source.new %(
+      expect_no_issues subject, <<-CRYSTAL
         # ameba:enable
         # ameba:disable
-      )
-      subject.catch(s).should be_valid
+        CRYSTAL
     end
 
     it "does not report if there are group names in the directive" do
-      s = Source.new %(
+      expect_no_issues subject, <<-CRYSTAL
         # ameba:disable Style Performance
-      )
-      subject.catch(s).should be_valid
+        CRYSTAL
     end
   end
 end
diff --git a/spec/ameba/rule/lint/empty_loop_spec.cr b/spec/ameba/rule/lint/empty_loop_spec.cr
index 26f63fba..d2a8c21e 100644
--- a/spec/ameba/rule/lint/empty_loop_spec.cr
+++ b/spec/ameba/rule/lint/empty_loop_spec.cr
@@ -5,7 +5,7 @@ module Ameba::Rule::Lint
     subject = EmptyLoop.new
 
     it "does not report if there are not empty loops" do
-      s = Source.new %(
+      expect_no_issues subject, <<-CRYSTAL
         a = 1
 
         while a < 10
@@ -19,54 +19,50 @@ module Ameba::Rule::Lint
         loop do
           a += 1
         end
-      )
-      subject.catch(s).should be_valid
+        CRYSTAL
     end
 
     it "reports if there is an empty while loop" do
-      s = Source.new %(
+      expect_issue subject, <<-CRYSTAL
         a = 1
         while true
+        # ^^^^^^^^ error: Empty loop detected
         end
-      )
-      subject.catch(s).should_not be_valid
+        CRYSTAL
     end
 
     it "doesn't report if while loop has non-literals in cond block" do
-      s = Source.new %(
+      expect_no_issues subject, <<-CRYSTAL
         a = 1
         while a = gets.to_s
           # nothing here
         end
-      )
-      subject.catch(s).should be_valid
+        CRYSTAL
     end
 
     it "reports if there is an empty until loop" do
-      s = Source.new %(
+      expect_issue subject, <<-CRYSTAL
         do_something
         until false
+        # ^^^^^^^^^ error: Empty loop detected
         end
-      )
-      subject.catch(s).should_not be_valid
+        CRYSTAL
     end
 
     it "doesn't report if until loop has non-literals in cond block" do
-      s = Source.new %(
+      expect_no_issues subject, <<-CRYSTAL
         until socket_open?
         end
-      )
-      subject.catch(s).should be_valid
+        CRYSTAL
     end
 
     it "reports if there an empty loop" do
-      s = Source.new %(
+      expect_issue subject, <<-CRYSTAL
         a = 1
         loop do
-
+        # ^^^^^ error: Empty loop detected
         end
-      )
-      subject.catch(s).should_not be_valid
+        CRYSTAL
     end
 
     it "reports rule, message and location" do
diff --git a/spec/ameba/rule/lint/hash_duplicated_key_spec.cr b/spec/ameba/rule/lint/hash_duplicated_key_spec.cr
index 43b5a447..def877f7 100644
--- a/spec/ameba/rule/lint/hash_duplicated_key_spec.cr
+++ b/spec/ameba/rule/lint/hash_duplicated_key_spec.cr
@@ -5,26 +5,32 @@ module Ameba::Rule::Lint
     subject = HashDuplicatedKey.new
 
     it "passes if there is no duplicated keys in a hash literals" do
-      s = Source.new %(
+      expect_no_issues subject, <<-CRYSTAL
         h = {"a" => 1, :a => 2, "b" => 3}
         h = {"a" => 1, "b" => 2, "c" => {"a" => 3, "b" => 4}}
         h = {} of String => String
-      )
-      subject.catch(s).should be_valid
+        CRYSTAL
     end
 
     it "fails if there is a duplicated key in a hash literal" do
-      s = Source.new %q(
+      expect_issue subject, <<-CRYSTAL
         h = {"a" => 1, "b" => 2, "a" => 3}
-      )
-      subject.catch(s).should_not be_valid
+          # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: Duplicated keys in hash literal: "a"
+        CRYSTAL
     end
 
     it "fails if there is a duplicated key in the inner hash literal" do
-      s = Source.new %q(
+      expect_issue subject, <<-CRYSTAL
         h = {"a" => 1, "b" => {"a" => 3, "b" => 4, "a" => 5}}
-      )
-      subject.catch(s).should_not be_valid
+                            # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: Duplicated keys in hash literal: "a"
+        CRYSTAL
+    end
+
+    it "reports multiple duplicated keys" do
+      expect_issue subject, <<-CRYSTAL
+        h = {"key1" => 1, "key1" => 2, "key2" => 3, "key2" => 4}
+          # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: Duplicated keys in hash literal: "key1", "key2"
+        CRYSTAL
     end
 
     it "reports rule, location and message" do
@@ -38,14 +44,5 @@ module Ameba::Rule::Lint
       issue.end_location.to_s.should eq "source.cr:1:24"
       issue.message.should eq %(Duplicated keys in hash literal: "a")
     end
-
-    it "reports multiple duplicated keys" do
-      s = Source.new %q(
-        h = {"key1" => 1, "key1" => 2, "key2" => 3, "key2" => 4}
-      )
-      subject.catch(s).should_not be_valid
-      issue = s.issues.first
-      issue.message.should eq %(Duplicated keys in hash literal: "key1", "key2")
-    end
   end
 end
diff --git a/spec/ameba/rule/lint/literal_in_interpolation_spec.cr b/spec/ameba/rule/lint/literal_in_interpolation_spec.cr
index 218d94d7..78487eec 100644
--- a/spec/ameba/rule/lint/literal_in_interpolation_spec.cr
+++ b/spec/ameba/rule/lint/literal_in_interpolation_spec.cr
@@ -5,15 +5,14 @@ module Ameba::Rule::Lint
 
   describe LiteralInInterpolation do
     it "passes with good interpolation examples" do
-      s = Source.new %q(
+      expect_no_issues subject, <<-CRYSTAL
         name = "Ary"
         "Hello, #{name}"
 
         "#{name}"
 
         "Name size: #{name.size}"
-      )
-      subject.catch(s).should be_valid
+        CRYSTAL
     end
 
     it "fails if there is useless interpolation" do
diff --git a/spec/ameba/rule/lint/rand_zero_spec.cr b/spec/ameba/rule/lint/rand_zero_spec.cr
index a86d30f2..cb5cc6d4 100644
--- a/spec/ameba/rule/lint/rand_zero_spec.cr
+++ b/spec/ameba/rule/lint/rand_zero_spec.cr
@@ -5,22 +5,25 @@ module Ameba::Rule::Lint
     subject = RandZero.new
 
     it "passes if it is not rand(1) or rand(0)" do
-      s = Source.new %(
+      expect_no_issues subject, <<-CRYSTAL
         rand(1.0)
         rand(0.11)
         rand(2)
-      )
-      subject.catch(s).should be_valid
+        CRYSTAL
     end
 
     it "fails if it is rand(0)" do
-      s = Source.new "rand(0)"
-      subject.catch(s).should_not be_valid
+      expect_issue subject, <<-CRYSTAL
+        rand(0)
+        # ^^^^^ error: rand(0) always returns 0
+        CRYSTAL
     end
 
     it "fails if it is rand(1)" do
-      s = Source.new "rand(1)"
-      subject.catch(s).should_not be_valid
+      expect_issue subject, <<-CRYSTAL
+        rand(1)
+        # ^^^^^ error: rand(1) always returns 0
+        CRYSTAL
     end
 
     it "reports rule, location and a message" do
diff --git a/spec/ameba/rule/lint/shadowing_local_outer_var_spec.cr b/spec/ameba/rule/lint/shadowing_outer_local_var_spec.cr
similarity index 68%
rename from spec/ameba/rule/lint/shadowing_local_outer_var_spec.cr
rename to spec/ameba/rule/lint/shadowing_outer_local_var_spec.cr
index 4b1e5799..5706841f 100644
--- a/spec/ameba/rule/lint/shadowing_local_outer_var_spec.cr
+++ b/spec/ameba/rule/lint/shadowing_outer_local_var_spec.cr
@@ -5,7 +5,7 @@ module Ameba::Rule::Lint
     subject = ShadowingOuterLocalVar.new
 
     it "doesn't report if there is no shadowing" do
-      source = Source.new %(
+      expect_no_issues subject, <<-CRYSTAL
         def some_method
           foo = 1
 
@@ -14,126 +14,117 @@ module Ameba::Rule::Lint
           end
 
           -> (baz : Int32) {}
-
           -> (bar : String) {}
         end
-      )
-
-      subject.catch(source).should be_valid
+        CRYSTAL
     end
 
     it "reports if there is a shadowing in a block" do
-      source = Source.new %(
+      expect_issue subject, <<-CRYSTAL
         def some_method
           foo = 1
 
           3.times do |foo|
+                    # ^ error: Shadowing outer local variable `foo`
           end
         end
-      )
-      subject.catch(source).should_not be_valid
+        CRYSTAL
     end
 
     it "does not report outer vars declared below shadowed block" do
-      source = Source.new %(
+      expect_no_issues subject, <<-CRYSTAL
         methods = klass.methods.select { |m| m.annotation(MyAnn) }
         m = methods.last
-      )
-      subject.catch(source).should be_valid
+        CRYSTAL
     end
 
     it "reports if there is a shadowing in a proc" do
-      source = Source.new %(
+      expect_issue subject, <<-CRYSTAL
         def some_method
           foo = 1
 
           -> (foo : Int32) {}
+            # ^ error: Shadowing outer local variable `foo`
         end
-      )
-      subject.catch(source).should_not be_valid
+        CRYSTAL
     end
 
     it "reports if there is a shadowing in an inner scope" do
-      source = Source.new %(
+      expect_issue subject, <<-CRYSTAL
         def foo
           foo = 1
 
           3.times do |i|
             3.times { |foo| foo }
+                     # ^ error: Shadowing outer local variable `foo`
           end
         end
-      )
-      subject.catch(source).should_not be_valid
+        CRYSTAL
     end
 
     it "reports if variable is shadowed twice" do
-      source = Source.new %(
+      expect_issue subject, <<-CRYSTAL
         foo = 1
 
         3.times do |foo|
+                  # ^ error: Shadowing outer local variable `foo`
           -> (foo : Int32) { foo + 1 }
+            # ^ error: Shadowing outer local variable `foo`
         end
-      )
-      subject.catch(source).should_not be_valid
-
-      source.issues.size.should eq 2
+        CRYSTAL
     end
 
     it "reports if a splat block argument shadows local var" do
-      source = Source.new %(
+      expect_issue subject, <<-CRYSTAL
         foo = 1
 
         3.times do |*foo|
+                   # ^ error: Shadowing outer local variable `foo`
         end
-      )
-      subject.catch(source).should_not be_valid
+        CRYSTAL
     end
 
     it "reports if a &block argument is shadowed" do
-      source = Source.new %(
+      expect_issue subject, <<-CRYSTAL
         def method_with_block(a, &block)
           3.times do |block|
+                    # ^ error: Shadowing outer local variable `block`
           end
         end
-      )
-      subject.catch(source).should_not be_valid
-      source.issues.first.message.should eq "Shadowing outer local variable `block`"
+        CRYSTAL
     end
 
     it "reports if there are multiple args and one shadows local var" do
-      source = Source.new %(
+      expect_issue subject, <<-CRYSTAL
         foo = 1
         [1, 2, 3].each_with_index do |i, foo|
+                                       # ^ error: Shadowing outer local variable `foo`
           i + foo
         end
-      )
-      subject.catch(source).should_not be_valid
-      source.issues.first.message.should eq "Shadowing outer local variable `foo`"
+        CRYSTAL
     end
 
     it "doesn't report if an outer var is reassigned in a block" do
-      source = Source.new %(
+      expect_no_issues subject, <<-CRYSTAL
         def foo
           foo = 1
           3.times do |i|
             foo = 2
           end
         end
-      )
-      subject.catch(source).should be_valid
+        CRYSTAL
     end
 
     it "doesn't report if an argument is a black hole '_'" do
-      source = Source.new %(
+      expect_no_issues subject, <<-CRYSTAL
         _ = 1
         3.times do |_|
         end
-      )
-      subject.catch(source).should be_valid
+        CRYSTAL
     end
 
     it "doesn't report if it shadows record type declaration" do
-      source = Source.new %(
+      expect_no_issues subject, <<-CRYSTAL
         class FooBar
           record Foo, index : String
 
@@ -142,12 +133,11 @@ module Ameba::Rule::Lint
             end
           end
         end
-      )
-      subject.catch(source).should be_valid
+        CRYSTAL
     end
 
     it "doesn't report if it shadows throwaway arguments" do
-      source = Source.new %(
+      expect_no_issues subject, <<-CRYSTAL
         data = [{1, "a"}, {2, "b"}, {3, "c"}]
 
         data.each do |_, string|
@@ -155,18 +145,16 @@ module Ameba::Rule::Lint
             puts string, number
           end
         end
-      )
-      subject.catch(source).should be_valid
+        CRYSTAL
     end
 
     it "does not report if argument shadows an ivar assignment" do
-      s = Source.new %(
+      expect_no_issues subject, <<-CRYSTAL
         def bar(@foo)
           @foo.try do |foo|
           end
         end
-      )
-      subject.catch(s).should be_valid
+        CRYSTAL
     end
 
     it "reports rule, location and message" do
@@ -185,7 +173,7 @@ module Ameba::Rule::Lint
 
     context "macro" do
       it "does not report shadowed vars in outer scope" do
-        source = Source.new %(
+        expect_no_issues subject, <<-CRYSTAL
           macro included
             def foo
               {% for ivar in instance_vars %}
@@ -197,12 +185,11 @@ module Ameba::Rule::Lint
               {% instance_vars.reject { |ivar| ivar } %}
             end
           end
-        )
-        subject.catch(source).should be_valid
+          CRYSTAL
       end
 
       it "does not report shadowed vars in macro within the same scope" do
-        source = Source.new %(
+        expect_no_issues subject, <<-CRYSTAL
           {% methods = klass.methods.select { |m| m.annotation(MyAnn) } %}
 
           {% for m, m_idx in methods %}
@@ -210,12 +197,11 @@ module Ameba::Rule::Lint
               {% d %}
             {% end %}
           {% end %}
-        )
-        subject.catch(source).should be_valid
+          CRYSTAL
       end
 
       it "does not report shadowed vars within nested macro" do
-        source = Source.new %(
+        expect_no_issues subject, <<-CRYSTAL
           module Foo
             macro included
               def foo
@@ -233,12 +219,11 @@ module Ameba::Rule::Lint
               end
             end
           end
-        )
-        subject.catch(source).should be_valid
+          CRYSTAL
       end
 
       it "does not report scoped vars to MacroFor" do
-        source = Source.new %(
+        expect_no_issues subject, <<-CRYSTAL
           struct Test
             def test
               {% for ivar in @type.instance_vars %}
@@ -248,8 +233,24 @@ module Ameba::Rule::Lint
               {% ["a", "b"].map { |ivar| puts ivar } %}
             end
           end
-        )
-        subject.catch(source).should be_valid
+          CRYSTAL
+      end
+
+      # https://github.com/crystal-ameba/ameba/issues/224#issuecomment-822245167
+      it "does not report scoped vars to MacroFor (2)" do
+        expect_no_issues subject, <<-CRYSTAL
+          struct Test
+            def test
+              {% begin %}
+                {% for ivar in @type.instance_vars %}
+                  {% var_type = ivar %}
+                {% end %}
+
+                {% ["a", "b"].map { |ivar| puts ivar } %}
+              {% end %}
+            end
+          end
+          CRYSTAL
       end
     end
   end
diff --git a/spec/ameba/rule/lint/syntax_spec.cr b/spec/ameba/rule/lint/syntax_spec.cr
index c46e52f3..2412b0b2 100644
--- a/spec/ameba/rule/lint/syntax_spec.cr
+++ b/spec/ameba/rule/lint/syntax_spec.cr
@@ -5,23 +5,22 @@ module Ameba::Rule::Lint
     subject = Syntax.new
 
     it "passes if there is no invalid syntax" do
-      s = Source.new %(
+      expect_no_issues subject, <<-CRYSTAL
         def hello
           puts "totally valid"
         rescue e: Exception
         end
-      )
-      subject.catch(s).should be_valid
+        CRYSTAL
     end
 
     it "fails if there is an invalid syntax" do
-      s = Source.new %(
+      expect_issue subject, <<-CRYSTAL
         def hello
           puts "invalid"
         rescue Exception => e
+                       # ^ error: expecting any of these tokens: ;, NEWLINE (not '=>')
         end
-      )
-      subject.catch(s).should_not be_valid
+        CRYSTAL
     end
 
     it "reports rule, location and message" do
diff --git a/spec/ameba/rule/lint/unneeded_disable_directive_spec.cr b/spec/ameba/rule/lint/unneeded_disable_directive_spec.cr
index cc21a00f..7186ff2d 100644
--- a/spec/ameba/rule/lint/unneeded_disable_directive_spec.cr
+++ b/spec/ameba/rule/lint/unneeded_disable_directive_spec.cr
@@ -5,17 +5,15 @@ module Ameba::Rule::Lint
     subject = UnneededDisableDirective.new
 
     it "passes if there are no comments" do
-      s = Source.new %(
+      expect_no_issues subject, <<-CRYSTAL
         a = 1
-      )
-      subject.catch(s).should be_valid
+        CRYSTAL
     end
 
     it "passes if there is disable directive" do
-      s = Source.new %(
+      expect_no_issues subject, <<-CRYSTAL
         a = 1 # my super var
-      )
-      subject.catch(s).should be_valid
+        CRYSTAL
     end
 
     it "doesn't report if there is disable directive and it is needed" do
@@ -48,33 +46,27 @@ module Ameba::Rule::Lint
     end
 
     it "fails if there is unneeded directive" do
-      s = Source.new %Q(
+      expect_issue subject, <<-CRYSTAL
         # ameba:disable #{NamedRule.name}
+        # ^{} error: Unnecessary disabling of #{NamedRule.name}
         a = 1
-      )
-      subject.catch(s).should_not be_valid
-      s.issues.first.message.should eq(
-        "Unnecessary disabling of #{NamedRule.name}"
-      )
+        CRYSTAL
     end
 
     it "fails if there is inline unneeded directive" do
-      s = Source.new %Q(a = 1 # ameba:disable #{NamedRule.name})
-      subject.catch(s).should_not be_valid
-      s.issues.first.message.should eq(
-        "Unnecessary disabling of #{NamedRule.name}"
-      )
+      expect_issue subject, <<-CRYSTAL
+        a = 1 # ameba:disable #{NamedRule.name}
+            # ^ error: Unnecessary disabling of #{NamedRule.name}
+        CRYSTAL
     end
 
     it "detects mixed inline directives" do
-      s = Source.new %Q(
+      expect_issue subject, <<-CRYSTAL
         # ameba:disable Rule1, Rule2
+        # ^{} error: Unnecessary disabling of Rule1, Rule2
         a = 1 # ameba:disable Rule3
-      ), "source.cr"
-      subject.catch(s).should_not be_valid
-      s.issues.size.should eq 2
-      s.issues.first.message.should contain "Rule1, Rule2"
-      s.issues.last.message.should contain "Rule3"
+            # ^ error: Unnecessary disabling of Rule3
+        CRYSTAL
     end
 
     it "fails if there is disabled UnneededDisableDirective" do
diff --git a/spec/ameba/rule/lint/useless_condition_in_when_spec.cr b/spec/ameba/rule/lint/useless_condition_in_when_spec.cr
index 3dadc3bb..9fffc4a9 100644
--- a/spec/ameba/rule/lint/useless_condition_in_when_spec.cr
+++ b/spec/ameba/rule/lint/useless_condition_in_when_spec.cr
@@ -5,25 +5,24 @@ module Ameba::Rule::Lint
 
   describe UselessConditionInWhen do
     it "passes if there is not useless condition" do
-      s = Source.new %(
+      expect_no_issues subject, <<-CRYSTAL
         case
         when utc?
           io << " UTC"
         when local?
           Format.new(" %:z").format(self, io) if utc?
         end
-      )
-      subject.catch(s).should be_valid
+        CRYSTAL
     end
 
     it "fails if there is useless if condition" do
-      s = Source.new %(
+      expect_issue subject, <<-CRYSTAL
         case
         when utc?
           io << " UTC" if utc?
+                        # ^^^^ error: Useless condition in when detected
         end
-      )
-      subject.catch(s).should_not be_valid
+        CRYSTAL
     end
 
     it "reports rule, location and message" do
diff --git a/spec/ameba/rule/metrics/cyclomatic_complexity_spec.cr b/spec/ameba/rule/metrics/cyclomatic_complexity_spec.cr
index eb4f5519..5692ae33 100644
--- a/spec/ameba/rule/metrics/cyclomatic_complexity_spec.cr
+++ b/spec/ameba/rule/metrics/cyclomatic_complexity_spec.cr
@@ -15,33 +15,35 @@ module Ameba::Rule::Metrics
         end
       end
     end
-  CODE
+    CODE
 
   describe CyclomaticComplexity do
     it "passes for empty methods" do
-      source = Source.new %(
+      expect_no_issues subject, <<-CRYSTAL
         def hello
         end
-      )
-      subject.catch(source).should be_valid
+        CRYSTAL
     end
 
     it "reports one issue for a complex method" do
-      subject.max_complexity = 5
+      rule = CyclomaticComplexity.new
+      rule.max_complexity = 5
+
       source = Source.new(complex_method, "source.cr")
-      subject.catch(source).should_not be_valid
+      rule.catch(source).should_not be_valid
 
       issue = source.issues.first
-      issue.rule.should eq subject
+      issue.rule.should eq rule
       issue.location.to_s.should eq "source.cr:1:5"
       issue.end_location.to_s.should eq "source.cr:1:9"
       issue.message.should eq "Cyclomatic complexity too high [8/5]"
     end
 
     it "doesn't report an issue for an increased threshold" do
-      subject.max_complexity = 100
-      source = Source.new(complex_method, "source.cr")
-      subject.catch(source).should be_valid
+      rule = CyclomaticComplexity.new
+      rule.max_complexity = 100
+
+      expect_no_issues rule, complex_method
     end
   end
 end
diff --git a/spec/ameba/rule/performance/any_after_filter_spec.cr b/spec/ameba/rule/performance/any_after_filter_spec.cr
index f95f395a..a7758533 100644
--- a/spec/ameba/rule/performance/any_after_filter_spec.cr
+++ b/spec/ameba/rule/performance/any_after_filter_spec.cr
@@ -49,6 +49,7 @@ module Ameba::Rule::Performance
       it "allows to configure object_call_names" do
         rule = Rule::Performance::AnyAfterFilter.new
         rule.filter_names = %w(select)
+
         expect_no_issues rule, <<-CRYSTAL
           [1, 2, 3].reject { |e| e > 2 }.any?
           CRYSTAL
diff --git a/spec/ameba/rule/performance/chained_call_with_no_bang_spec.cr b/spec/ameba/rule/performance/chained_call_with_no_bang_spec.cr
index ad3cda81..73100d39 100644
--- a/spec/ameba/rule/performance/chained_call_with_no_bang_spec.cr
+++ b/spec/ameba/rule/performance/chained_call_with_no_bang_spec.cr
@@ -47,6 +47,7 @@ module Ameba::Rule::Performance
       it "allows to configure `call_names`" do
         rule = ChainedCallWithNoBang.new
         rule.call_names = %w(uniq)
+
         expect_no_issues rule, <<-CRYSTAL
           [1, 2, 3].select { |e| e > 2 }.reverse
           CRYSTAL
diff --git a/spec/ameba/rule/performance/compact_after_map_spec.cr b/spec/ameba/rule/performance/compact_after_map_spec.cr
index 3d3a7625..9c7a72e3 100644
--- a/spec/ameba/rule/performance/compact_after_map_spec.cr
+++ b/spec/ameba/rule/performance/compact_after_map_spec.cr
@@ -5,39 +5,35 @@ module Ameba::Rule::Performance
 
   describe CompactAfterMap do
     it "passes if there is no potential performance improvements" do
-      source = Source.new %(
+      expect_no_issues subject, <<-CRYSTAL
         (1..3).compact_map(&.itself)
-      )
-      subject.catch(source).should be_valid
+        CRYSTAL
     end
 
     it "passes if there is map followed by a bang call" do
-      source = Source.new %(
+      expect_no_issues subject, <<-CRYSTAL
         (1..3).map(&.itself).compact!
-      )
-      subject.catch(source).should be_valid
+        CRYSTAL
     end
 
     it "reports if there is map followed by compact call" do
-      source = Source.new %(
+      expect_issue subject, <<-CRYSTAL
         (1..3).map(&.itself).compact
-      )
-      subject.catch(source).should_not be_valid
+             # ^^^^^^^^^^^^^^^^^^^^^^ error: Use `compact_map {...}` instead of `map {...}.compact`
+        CRYSTAL
     end
 
     it "does not report if source is a spec" do
-      source = Source.new %(
+      expect_no_issues subject, path: "source_spec.cr", code: <<-CRYSTAL
         (1..3).map(&.itself).compact
-      ), "source_spec.cr"
-      subject.catch(source).should be_valid
+        CRYSTAL
     end
 
     context "macro" do
       it "doesn't report in macro scope" do
-        source = Source.new %(
+        expect_no_issues subject, <<-CRYSTAL
           {{ [1, 2, 3].map(&.to_s).compact }}
-        )
-        subject.catch(source).should be_valid
+          CRYSTAL
       end
     end
 
diff --git a/spec/ameba/rule/performance/first_last_after_filter_spec.cr b/spec/ameba/rule/performance/first_last_after_filter_spec.cr
index a4698c69..55823d9c 100644
--- a/spec/ameba/rule/performance/first_last_after_filter_spec.cr
+++ b/spec/ameba/rule/performance/first_last_after_filter_spec.cr
@@ -5,74 +5,70 @@ module Ameba::Rule::Performance
 
   describe FirstLastAfterFilter do
     it "passes if there is no potential performance improvements" do
-      source = Source.new %(
+      expect_no_issues subject, <<-CRYSTAL
         [1, 2, 3].select { |e| e > 1 }
         [1, 2, 3].reverse.select { |e| e > 1 }
         [1, 2, 3].reverse.last
         [1, 2, 3].reverse.first
         [1, 2, 3].reverse.first
-      )
-      subject.catch(source).should be_valid
+        CRYSTAL
     end
 
     it "reports if there is select followed by last" do
-      source = Source.new %(
+      expect_issue subject, <<-CRYSTAL
         [1, 2, 3].select { |e| e > 2 }.last
-      )
-      subject.catch(source).should_not be_valid
+                # ^^^^^^^^^^^^^^^^^^^^^^^^^^ error: Use `reverse_each.find {...}` instead of `select {...}.last`
+        CRYSTAL
     end
 
     it "does not report if source is a spec" do
-      source = Source.new %(
+      expect_no_issues subject, path: "source_spec.cr", code: <<-CRYSTAL
         [1, 2, 3].select { |e| e > 2 }.last
-      ), "source_spec.cr"
-      subject.catch(source).should be_valid
+        CRYSTAL
     end
 
     it "reports if there is select followed by last?" do
-      source = Source.new %(
+      expect_issue subject, <<-CRYSTAL
         [1, 2, 3].select { |e| e > 2 }.last?
-      )
-      subject.catch(source).should_not be_valid
+                # ^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: Use `reverse_each.find {...}` instead of `select {...}.last?`
+        CRYSTAL
     end
 
     it "reports if there is select followed by first" do
-      source = Source.new %(
+      expect_issue subject, <<-CRYSTAL
         [1, 2, 3].select { |e| e > 2 }.first
-      )
-      subject.catch(source).should_not be_valid
+                # ^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: Use `find {...}` instead of `select {...}.first`
+        CRYSTAL
     end
 
     it "does not report if there is selected followed by first with arguments" do
-      source = Source.new %(
+      expect_no_issues subject, <<-CRYSTAL
         [1, 2, 3].select { |n| n % 2 == 0 }.first(2)
-      )
-      subject.catch(source).should be_valid
+        CRYSTAL
     end
 
     it "reports if there is select followed by first?" do
-      source = Source.new %(
+      expect_issue subject, <<-CRYSTAL
         [1, 2, 3].select { |e| e > 2 }.first?
-      )
-      subject.catch(source).should_not be_valid
+                # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: Use `find {...}` instead of `select {...}.first?`
+        CRYSTAL
     end
 
     it "does not report if there is select followed by any other call" do
-      source = Source.new %(
+      expect_no_issues subject, <<-CRYSTAL
         [1, 2, 3].select { |e| e > 2 }.size
         [1, 2, 3].select { |e| e > 2 }.any?
-      )
-      subject.catch(source).should be_valid
+        CRYSTAL
     end
 
     context "properties" do
       it "allows to configure object_call_names" do
-        source = Source.new %(
-          [1, 2, 3].select { |e| e > 2 }.first
-        )
         rule = Rule::Performance::FirstLastAfterFilter.new
         rule.filter_names = %w(reject)
-        rule.catch(source).should be_valid
+
+        expect_no_issues rule, <<-CRYSTAL
+          [1, 2, 3].select { |e| e > 2 }.first
+          CRYSTAL
       end
     end
 
@@ -91,58 +87,12 @@ module Ameba::Rule::Performance
       issue.message.should eq "Use `find {...}` instead of `select {...}.first`"
     end
 
-    it "reports a correct message for first?" do
-      s = Source.new %(
-        [1, 2, 3].select { |e| e > 2 }.first?
-      ), "source.cr"
-      subject.catch(s).should_not be_valid
-      s.issues.size.should eq 1
-
-      issue = s.issues.first
-      issue.rule.should_not be_nil
-      issue.location.to_s.should eq "source.cr:1:11"
-      issue.end_location.to_s.should eq "source.cr:1:38"
-
-      issue.message.should eq "Use `find {...}` instead of `select {...}.first?`"
-    end
-
-    it "reports rule, pos and reverse message" do
-      s = Source.new %(
-        [1, 2, 3].select { |e| e > 2 }.last
-      ), "source.cr"
-      subject.catch(s).should_not be_valid
-      s.issues.size.should eq 1
-
-      issue = s.issues.first
-      issue.rule.should_not be_nil
-      issue.location.to_s.should eq "source.cr:1:11"
-      issue.end_location.to_s.should eq "source.cr:1:36"
-
-      issue.message.should eq "Use `reverse_each.find {...}` instead of `select {...}.last`"
-    end
-
     context "macro" do
       it "doesn't report in macro scope" do
-        source = Source.new %(
-          {{[1, 2, 3].select { |e| e > 2  }.last }}
-        )
-        subject.catch(source).should be_valid
+        expect_no_issues subject, <<-CRYSTAL
+          {{ [1, 2, 3].select { |e| e > 2  }.last }}
+          CRYSTAL
       end
     end
-
-    it "reports a correct message for last?" do
-      s = Source.new %(
-        [1, 2, 3].select { |e| e > 2 }.last?
-      ), "source.cr"
-      subject.catch(s).should_not be_valid
-      s.issues.size.should eq 1
-
-      issue = s.issues.first
-      issue.rule.should_not be_nil
-      issue.location.to_s.should eq "source.cr:1:11"
-      issue.end_location.to_s.should eq "source.cr:1:37"
-
-      issue.message.should eq "Use `reverse_each.find {...}` instead of `select {...}.last?`"
-    end
   end
 end
diff --git a/spec/ameba/rule/performance/flatten_after_map_spec.cr b/spec/ameba/rule/performance/flatten_after_map_spec.cr
index 14d63814..54796380 100644
--- a/spec/ameba/rule/performance/flatten_after_map_spec.cr
+++ b/spec/ameba/rule/performance/flatten_after_map_spec.cr
@@ -5,32 +5,29 @@ module Ameba::Rule::Performance
 
   describe FlattenAfterMap do
     it "passes if there is no potential performance improvements" do
-      source = Source.new %(
+      expect_no_issues subject, <<-CRYSTAL
         %w[Alice Bob].flat_map(&.chars)
-      )
-      subject.catch(source).should be_valid
+        CRYSTAL
     end
 
     it "reports if there is map followed by flatten call" do
-      source = Source.new %(
+      expect_issue subject, <<-CRYSTAL
         %w[Alice Bob].map(&.chars).flatten
-      )
-      subject.catch(source).should_not be_valid
+                    # ^^^^^^^^^^^^^^^^^^^^^ error: Use `flat_map {...}` instead of `map {...}.flatten`
+        CRYSTAL
     end
 
     it "does not report is source is a spec" do
-      source = Source.new %(
+      expect_no_issues subject, path: "source_spec.cr", code: <<-CRYSTAL
         %w[Alice Bob].map(&.chars).flatten
-      ), "source_spec.cr"
-      subject.catch(source).should be_valid
+        CRYSTAL
     end
 
     context "macro" do
       it "doesn't report in macro scope" do
-        source = Source.new %(
+        expect_no_issues subject, <<-CRYSTAL
           {{ %w[Alice Bob].map(&.chars).flatten }}
-        )
-        subject.catch(source).should be_valid
+          CRYSTAL
       end
     end
 
diff --git a/spec/ameba/rule/performance/map_instead_of_block_spec.cr b/spec/ameba/rule/performance/map_instead_of_block_spec.cr
index d51f8556..95cfd901 100644
--- a/spec/ameba/rule/performance/map_instead_of_block_spec.cr
+++ b/spec/ameba/rule/performance/map_instead_of_block_spec.cr
@@ -5,47 +5,44 @@ module Ameba::Rule::Performance
 
   describe MapInsteadOfBlock do
     it "passes if there is no potential performance improvements" do
-      source = Source.new %(
+      expect_no_issues subject, <<-CRYSTAL
         (1..3).sum(&.*(2))
         (1..3).product(&.*(2))
-      )
-      subject.catch(source).should be_valid
+        CRYSTAL
     end
 
     it "reports if there is map followed by sum without a block" do
-      source = Source.new %(
+      expect_issue subject, <<-CRYSTAL
         (1..3).map(&.to_u64).sum
-      )
-      subject.catch(source).should_not be_valid
+             # ^^^^^^^^^^^^^^^^^^ error: Use `sum {...}` instead of `map {...}.sum`
+        CRYSTAL
     end
 
     it "does not report if source is a spec" do
-      source = Source.new %(
+      expect_no_issues subject, path: "source_spec.cr", code: <<-CRYSTAL
         (1..3).map(&.to_s).join
-      ), "source_spec.cr"
-      subject.catch(source).should be_valid
+        CRYSTAL
     end
 
     it "reports if there is map followed by sum without a block (with argument)" do
-      source = Source.new %(
+      expect_issue subject, <<-CRYSTAL
         (1..3).map(&.to_u64).sum(0)
-      )
-      subject.catch(source).should_not be_valid
+             # ^^^^^^^^^^^^^^^^^^ error: Use `sum {...}` instead of `map {...}.sum`
+        CRYSTAL
     end
 
     it "reports if there is map followed by sum with a block" do
-      source = Source.new %(
+      expect_issue subject, <<-CRYSTAL
         (1..3).map(&.to_u64).sum(&.itself)
-      )
-      subject.catch(source).should_not be_valid
+             # ^^^^^^^^^^^^^^^^^^ error: Use `sum {...}` instead of `map {...}.sum`
+        CRYSTAL
     end
 
     context "macro" do
       it "doesn't report in macro scope" do
-        source = Source.new %(
+        expect_no_issues subject, <<-CRYSTAL
           {{ [1, 2, 3].map(&.to_u64).sum }}
-        )
-        subject.catch(source).should be_valid
+          CRYSTAL
       end
     end
 
diff --git a/spec/ameba/rule/performance/size_after_filter_spec.cr b/spec/ameba/rule/performance/size_after_filter_spec.cr
index a467d551..27034bbf 100644
--- a/spec/ameba/rule/performance/size_after_filter_spec.cr
+++ b/spec/ameba/rule/performance/size_after_filter_spec.cr
@@ -5,7 +5,7 @@ module Ameba::Rule::Performance
 
   describe SizeAfterFilter do
     it "passes if there is no potential performance improvements" do
-      source = Source.new %(
+      expect_no_issues subject, <<-CRYSTAL
         [1, 2, 3].select { |e| e > 2 }
         [1, 2, 3].reject { |e| e < 2 }
         [1, 2, 3].count { |e| e > 2 && e.odd? }
@@ -13,55 +13,52 @@ module Ameba::Rule::Performance
 
         User.select("field AS name").count
         Company.select(:value).count
-      )
-      subject.catch(source).should be_valid
+        CRYSTAL
     end
 
     it "reports if there is a select followed by size" do
-      source = Source.new %(
+      expect_issue subject, <<-CRYSTAL
         [1, 2, 3].select { |e| e > 2 }.size
-      )
-      subject.catch(source).should_not be_valid
+                # ^^^^^^^^^^^^^^^^^^^^^^^^^^ error: Use `count {...}` instead of `select {...}.size`.
+        CRYSTAL
     end
 
     it "does not report if source is a spec" do
-      source = Source.new %(
+      expect_no_issues subject, path: "source_spec.cr", code: <<-CRYSTAL
         [1, 2, 3].select { |e| e > 2 }.size
-      ), "source_spec.cr"
-      subject.catch(source).should be_valid
+        CRYSTAL
     end
 
     it "reports if there is a reject followed by size" do
-      source = Source.new %(
+      expect_issue subject, <<-CRYSTAL
         [1, 2, 3].reject { |e| e < 2 }.size
-      )
-      subject.catch(source).should_not be_valid
+                # ^^^^^^^^^^^^^^^^^^^^^^^^^^ error: Use `count {...}` instead of `reject {...}.size`.
+        CRYSTAL
     end
 
     it "reports if a block shorthand used" do
-      source = Source.new %(
+      expect_issue subject, <<-CRYSTAL
         [1, 2, 3].reject(&.empty?).size
-      )
-      subject.catch(source).should_not be_valid
+                # ^^^^^^^^^^^^^^^^^^^^^^ error: Use `count {...}` instead of `reject {...}.size`.
+        CRYSTAL
     end
 
     context "properties" do
       it "allows to configure object caller names" do
-        source = Source.new %(
-          [1, 2, 3].reject(&.empty?).size
-        )
         rule = Rule::Performance::SizeAfterFilter.new
         rule.filter_names = %w(select)
-        rule.catch(source).should be_valid
+
+        expect_no_issues rule, <<-CRYSTAL
+          [1, 2, 3].reject(&.empty?).size
+          CRYSTAL
       end
     end
 
     context "macro" do
       it "doesn't report in macro scope" do
-        source = Source.new %(
+        expect_no_issues subject, <<-CRYSTAL
           {{[1, 2, 3].select { |v| v > 1 }.size}}
-        )
-        subject.catch(source).should be_valid
+          CRYSTAL
       end
     end
 
diff --git a/src/ameba/ast/scope.cr b/src/ameba/ast/scope.cr
index bacf4258..bcae082c 100644
--- a/src/ameba/ast/scope.cr
+++ b/src/ameba/ast/scope.cr
@@ -71,7 +71,7 @@ module Ameba::AST
       ivariables << InstanceVariable.new(node)
     end
 
-    # Returns variable by its name or nil if it does not exist.
+    # Returns variable by its name or `nil` if it does not exist.
     #
     # ```
     # scope = Scope.new(class_node, nil)
@@ -91,13 +91,13 @@ module Ameba::AST
       find_variable(name).try &.assign(node, self)
     end
 
-    # Returns true if current scope represents a block (or proc),
-    # false if not.
+    # Returns `true` if current scope represents a block (or proc),
+    # `false` otherwise.
     def block?
       node.is_a?(Crystal::Block) || node.is_a?(Crystal::ProcLiteral)
     end
 
-    # Returns true if current scope represents a spawn block, e. g.
+    # Returns `true` if current scope represents a spawn block, e. g.
     #
     # ```
     # spawn do
@@ -110,18 +110,19 @@ module Ameba::AST
       call.try(&.name) == "spawn"
     end
 
-    # Returns true if current scope sits inside a macro.
+    # Returns `true` if current scope sits inside a macro.
     def in_macro?
-      node.is_a?(Crystal::Macro) || !!outer_scope.try(&.in_macro?)
+      (node.is_a?(Crystal::Macro) || node.is_a?(Crystal::MacroFor)) ||
+        !!outer_scope.try(&.in_macro?)
     end
 
-    # Returns true instance variable assinged in this scope.
+    # Returns `true` if instance variable is assinged in this scope.
     def assigns_ivar?(name)
       arguments.find(&.name.== name) &&
         ivariables.find(&.name.== "@#{name}")
     end
 
-    # Returns true if and only if current scope represents some
+    # Returns `true` if and only if current scope represents some
     # type definition, for example a class.
     def type_definition?
       node.is_a?(Crystal::ClassDef) ||
@@ -133,7 +134,7 @@ module Ameba::AST
     end
 
     # Returns true if current scope (or any of inner scopes) references variable,
-    # false if not.
+    # `false` otherwise.
     def references?(variable : Variable, check_inner_scopes = true)
       variable.references.any? do |reference|
         return true if reference.scope == self
@@ -141,17 +142,17 @@ module Ameba::AST
       end || variable.used_in_macro?
     end
 
-    # Returns true if current scope is a def, false if not.
+    # Returns `true` if current scope is a def, `false` otherwise.
     def def?
       node.is_a?(Crystal::Def)
     end
 
-    # Returns true if this scope is a top level scope, false if not.
+    # Returns `true` if this scope is a top level scope, `false` otherwise.
     def top_level?
       outer_scope.nil?
     end
 
-    # Returns true if var is an argument in current scope, false if not.
+    # Returns true if var is an argument in current scope, `false` otherwise.
     def arg?(var)
       case current_node = node
       when Crystal::Def
@@ -169,7 +170,7 @@ module Ameba::AST
       args.any? { |arg| arg.name == var.name && arg.location == var.location }
     end
 
-    # Returns true if the `node` represents exactly
+    # Returns `true` if the *node* represents exactly
     # the same Crystal node as `@node`.
     def eql?(node)
       node == @node &&
diff --git a/src/ameba/ast/visitors/node_visitor.cr b/src/ameba/ast/visitors/node_visitor.cr
index 9119b22c..a37eea08 100644
--- a/src/ameba/ast/visitors/node_visitor.cr
+++ b/src/ameba/ast/visitors/node_visitor.cr
@@ -46,7 +46,9 @@ module Ameba::AST
 
     {% for name in NODES %}
       # A visit callback for `Crystal::{{name}}` node.
-      # Returns true meaning that child nodes will be traversed as well.
+      #
+      # Returns `true` if the child nodes should be traversed as well,
+      # `false` otherwise.
       def visit(node : Crystal::{{name}})
         return false if skip?(node)
 
diff --git a/src/ameba/ast/visitors/scope_visitor.cr b/src/ameba/ast/visitors/scope_visitor.cr
index aaae84ea..06931ff3 100644
--- a/src/ameba/ast/visitors/scope_visitor.cr
+++ b/src/ameba/ast/visitors/scope_visitor.cr
@@ -3,19 +3,39 @@ require "./base_visitor"
 module Ameba::AST
   # AST Visitor that traverses the source and constructs scopes.
   class ScopeVisitor < BaseVisitor
+    # Non-exhaustive list of nodes to be visited by Ameba's rules.
+    NODES = [
+      ClassDef,
+      ModuleDef,
+      EnumDef,
+      LibDef,
+      FunDef,
+      TypeDef,
+      TypeOf,
+      CStructOrUnionDef,
+      ProcLiteral,
+      Block,
+      Macro,
+      MacroFor,
+    ]
+
     SUPER_NODE_NAME  = "super"
     RECORD_NODE_NAME = "record"
 
     @scope_queue = [] of Scope
     @current_scope : Scope
+    @current_assign : Crystal::ASTNode?
+    @skip : Array(Crystal::ASTNode.class)?
 
-    def initialize(@rule, @source)
+    def initialize(@rule, @source, skip = nil)
+      @skip = skip.try &.map(&.as(Crystal::ASTNode.class))
       @current_scope = Scope.new(@source.ast) # top level scope
       @source.ast.accept self
       @scope_queue.each { |scope| @rule.test @source, scope.node, scope }
     end
 
     private def on_scope_enter(node)
+      return if skip?(node)
       @current_scope = Scope.new(node, @current_scope)
     end
 
@@ -36,73 +56,18 @@ module Ameba::AST
       on_scope_end(node) if @current_scope.eql?(node)
     end
 
-    # :nodoc:
-    def visit(node : Crystal::ClassDef)
-      on_scope_enter(node)
-    end
-
-    # :nodoc:
-    def visit(node : Crystal::ModuleDef)
-      on_scope_enter(node)
-    end
-
-    # :nodoc:
-    def visit(node : Crystal::EnumDef)
-      on_scope_enter(node)
-    end
-
-    # :nodoc:
-    def visit(node : Crystal::LibDef)
-      on_scope_enter(node)
-    end
-
-    # :nodoc:
-    def visit(node : Crystal::FunDef)
-      on_scope_enter(node)
-    end
-
-    # :nodoc:
-    def visit(node : Crystal::TypeDef)
-      on_scope_enter(node)
-    end
-
-    # :nodoc:
-    def visit(node : Crystal::TypeOf)
-      on_scope_enter(node)
-    end
-
-    # :nodoc:
-    def visit(node : Crystal::CStructOrUnionDef)
-      on_scope_enter(node)
-    end
+    {% for name in NODES %}
+      # :nodoc:
+      def visit(node : Crystal::{{name}})
+        on_scope_enter(node)
+      end
+    {% end %}
 
     # :nodoc:
     def visit(node : Crystal::Def)
       node.name == "->" || on_scope_enter(node)
     end
 
-    # :nodoc:
-    def visit(node : Crystal::ProcLiteral)
-      on_scope_enter(node)
-    end
-
-    # :nodoc:
-    def visit(node : Crystal::Block)
-      on_scope_enter(node)
-    end
-
-    # :nodoc:
-    def visit(node : Crystal::Macro)
-      on_scope_enter(node)
-    end
-
-    # :nodoc:
-    def visit(node : Crystal::MacroFor)
-      on_scope_enter(node)
-    end
-
-    @current_assign : Crystal::ASTNode?
-
     # :nodoc:
     def visit(node : Crystal::Assign | Crystal::OpAssign | Crystal::MultiAssign | Crystal::UninitializedVar)
       @current_assign = node
@@ -182,5 +147,9 @@ module Ameba::AST
     private def record_macro?(node)
       node.name == RECORD_NODE_NAME && node.args.first?.is_a?(Crystal::Path)
     end
+
+    private def skip?(node)
+      !!@skip.try(&.includes?(node.class))
+    end
   end
 end
diff --git a/src/ameba/rule/lint/shadowing_local_outer_var.cr b/src/ameba/rule/lint/shadowing_outer_local_var.cr
similarity index 89%
rename from src/ameba/rule/lint/shadowing_local_outer_var.cr
rename to src/ameba/rule/lint/shadowing_outer_local_var.cr
index 8f70a285..d9abaec8 100644
--- a/src/ameba/rule/lint/shadowing_local_outer_var.cr
+++ b/src/ameba/rule/lint/shadowing_outer_local_var.cr
@@ -39,7 +39,10 @@ module Ameba::Rule::Lint
     MSG = "Shadowing outer local variable `%s`"
 
     def test(source)
-      AST::ScopeVisitor.new self, source
+      AST::ScopeVisitor.new self, source, skip: [
+        Crystal::Macro,
+        Crystal::MacroFor,
+      ]
     end
 
     def test(source, node : Crystal::ProcLiteral, scope : AST::Scope)
@@ -51,9 +54,7 @@ module Ameba::Rule::Lint
     end
 
     private def find_shadowing(source, scope)
-      outer_scope = scope.outer_scope
-
-      return if outer_scope.nil? || outer_scope.in_macro?
+      return unless outer_scope = scope.outer_scope
 
       scope.arguments.reject(&.ignored?).each do |arg|
         variable = outer_scope.find_variable(arg.name)