diff --git a/src/compiler/crystal/codegen/codegen.cr b/src/compiler/crystal/codegen/codegen.cr
index c40b58ab1040..df6afa474132 100644
--- a/src/compiler/crystal/codegen/codegen.cr
+++ b/src/compiler/crystal/codegen/codegen.cr
@@ -257,7 +257,6 @@ module Crystal
       emit_vars_debug_info(@program.vars) if @debug.variables?
     end
 
-    getter llvm_typer
     getter llvm_context
 
     def new_builder(llvm_context)
diff --git a/src/compiler/crystal/semantic/abstract_def_checker.cr b/src/compiler/crystal/semantic/abstract_def_checker.cr
index 46aa702d805e..418cf388c609 100644
--- a/src/compiler/crystal/semantic/abstract_def_checker.cr
+++ b/src/compiler/crystal/semantic/abstract_def_checker.cr
@@ -230,10 +230,7 @@ class Crystal::AbstractDefChecker
   end
 
   private def report_warning(node, message)
-    return unless @program.warnings.all?
-    return if @program.ignore_warning_due_to_location?(node.location)
-
-    @program.warning_failures << node.warning(message)
+    @program.report_warning(node, message)
   end
 
   class ReplacePathWithTypeVar < Visitor
diff --git a/src/compiler/crystal/semantic/warnings.cr b/src/compiler/crystal/semantic/warnings.cr
new file mode 100644
index 000000000000..d74f6e495870
--- /dev/null
+++ b/src/compiler/crystal/semantic/warnings.cr
@@ -0,0 +1,10 @@
+module Crystal
+  class Program
+    def report_warning(node : ASTNode, message : String)
+      return unless self.warnings.all?
+      return if self.ignore_warning_due_to_location?(node.location)
+
+      self.warning_failures << node.warning(message)
+    end
+  end
+end
diff --git a/src/compiler/crystal/syntax/ast.cr b/src/compiler/crystal/syntax/ast.cr
index 7b5b8be6ea42..6baed31bd27d 100644
--- a/src/compiler/crystal/syntax/ast.cr
+++ b/src/compiler/crystal/syntax/ast.cr
@@ -539,7 +539,7 @@ module Crystal
     property block_arg : ASTNode?
     property named_args : Array(NamedArgument)?
     property name_location : Location?
-    property name_size = -1
+    @name_size = -1
     property doc : String?
     property visibility = Visibility::Public
     property? global : Bool
@@ -575,6 +575,8 @@ module Crystal
       @name_size
     end
 
+    setter name_size
+
     def accept_children(visitor)
       @obj.try &.accept visitor
       @args.each &.accept visitor
diff --git a/src/compiler/crystal/tools/init.cr b/src/compiler/crystal/tools/init.cr
index 7a191055ea5f..a559ea129089 100644
--- a/src/compiler/crystal/tools/init.cr
+++ b/src/compiler/crystal/tools/init.cr
@@ -206,7 +206,7 @@ module Crystal
 
     class InitProject
       getter config : Config
-      getter views : Array(View)?
+      @views : Array(View)?
 
       def initialize(@config : Config)
       end
diff --git a/src/compiler/crystal/types.cr b/src/compiler/crystal/types.cr
index b41522c73bd7..f74d42d9c1d1 100644
--- a/src/compiler/crystal/types.cr
+++ b/src/compiler/crystal/types.cr
@@ -1192,10 +1192,6 @@ module Crystal
       superclass.try &.add_subclass(self)
     end
 
-    def struct?
-      @struct
-    end
-
     def has_attribute?(name)
       return true if packed? && name == "Packed"
       false
@@ -2099,10 +2095,6 @@ module Crystal
       end
     end
 
-    def filter_by_responds_to(name)
-      including_types.try &.filter_by_responds_to(name)
-    end
-
     def filter_by_responds_to(name)
       @generic_type.filter_by_responds_to(name) ? self : nil
     end
diff --git a/src/compiler/crystal/util.cr b/src/compiler/crystal/util.cr
index 9e5ef4a69bfa..10caed8bfbca 100644
--- a/src/compiler/crystal/util.cr
+++ b/src/compiler/crystal/util.cr
@@ -1,5 +1,7 @@
 module Crystal
-  def self.relative_filename(filename : String) : String
+  def self.relative_filename(filename)
+    return filename unless filename.is_a?(String)
+
     if base_file = filename.lchop? Dir.current
       if file_prefix = base_file.lchop? '/'
         return file_prefix
@@ -9,10 +11,6 @@ module Crystal
     filename
   end
 
-  def self.relative_filename(filename)
-    filename
-  end
-
   def self.error(msg, color, exit_code = 1, stderr = STDERR, leading_error = true)
     stderr.print "Error: ".colorize.toggle(color).red.bold if leading_error
     stderr.puts msg.colorize.toggle(color).bright
diff --git a/src/io/byte_format.cr b/src/io/byte_format.cr
index ff28be93f6e8..6f6b6a1082cd 100644
--- a/src/io/byte_format.cr
+++ b/src/io/byte_format.cr
@@ -43,8 +43,6 @@ module IO::ByteFormat
   abstract def encode(int : UInt64, io : IO)
   abstract def encode(int : Int128, io : IO)
   abstract def encode(int : UInt128, io : IO)
-  abstract def encode(int : Float32, io : IO)
-  abstract def encode(int : Float64, io : IO)
 
   abstract def encode(int : Int8, bytes : Bytes)
   abstract def encode(int : UInt8, bytes : Bytes)
@@ -56,8 +54,6 @@ module IO::ByteFormat
   abstract def encode(int : UInt64, bytes : Bytes)
   abstract def encode(int : Int128, bytes : Bytes)
   abstract def encode(int : UInt128, bytes : Bytes)
-  abstract def encode(int : Float32, bytes : Bytes)
-  abstract def encode(int : Float64, bytes : Bytes)
 
   abstract def decode(int : Int8.class, io : IO)
   abstract def decode(int : UInt8.class, io : IO)
@@ -69,8 +65,6 @@ module IO::ByteFormat
   abstract def decode(int : UInt64.class, io : IO)
   abstract def decode(int : Int128.class, io : IO)
   abstract def decode(int : UInt128.class, io : IO)
-  abstract def decode(int : Float32.class, io : IO)
-  abstract def decode(int : Float64.class, io : IO)
 
   abstract def decode(int : Int8.class, bytes : Bytes)
   abstract def decode(int : UInt8.class, bytes : Bytes)
@@ -82,8 +76,6 @@ module IO::ByteFormat
   abstract def decode(int : UInt64.class, bytes : Bytes)
   abstract def decode(int : Int128.class, bytes : Bytes)
   abstract def decode(int : UInt128.class, bytes : Bytes)
-  abstract def decode(int : Float32.class, bytes : Bytes)
-  abstract def decode(int : Float64.class, bytes : Bytes)
 
   def encode(float : Float32, io : IO)
     encode(float.unsafe_as(Int32), io)
diff --git a/src/llvm/builder.cr b/src/llvm/builder.cr
index 4a1a99bc2dcf..7180212fbbff 100644
--- a/src/llvm/builder.cr
+++ b/src/llvm/builder.cr
@@ -127,7 +127,7 @@ class LLVM::Builder
     Value.new LibLLVM.build_extract_value(self, value, index, name)
   end
 
-  {% for name in %w(bit_cast si2fp ui2fp zext sext trunc fpext fptrunc fp2si fp2ui si2fp ui2fp int2ptr ptr2int) %}
+  {% for name in %w(bit_cast zext sext trunc fpext fptrunc fp2si fp2ui si2fp ui2fp int2ptr ptr2int) %}
     def {{name.id}}(value, type, name = "")
       # check_type({{name}}, type)
       # check_value(value)
diff --git a/src/mime/multipart.cr b/src/mime/multipart.cr
index d5ba88c32388..f5126fe057f7 100644
--- a/src/mime/multipart.cr
+++ b/src/mime/multipart.cr
@@ -83,7 +83,7 @@ module MIME::Multipart
 
   # Yields a `Multipart::Builder` to the given block, writing to *io* and
   # using *boundary*. `#finish` is automatically called on the builder.
-  def self.build(io, boundary = Multipart.generate_boundary)
+  def self.build(io : IO, boundary : String = Multipart.generate_boundary)
     builder = Builder.new(io, boundary)
     yield builder
     builder.finish
@@ -91,7 +91,7 @@ module MIME::Multipart
 
   # Yields a `Multipart::Builder` to the given block, returning the generated
   # message as a `String`.
-  def self.build(boundary = Multipart.generate_boundary)
+  def self.build(boundary : String = Multipart.generate_boundary)
     String.build do |io|
       build(io, boundary) { |g| yield g }
     end
@@ -104,7 +104,7 @@ module MIME::Multipart
   #
   # MIME::Multipart.generate_boundary # => "---------------------------dQu6bXHYb4m5zrRC3xPTGwV"
   # ```
-  def self.generate_boundary
+  def self.generate_boundary : String
     "--------------------------#{Random::Secure.urlsafe_base64(18)}"
   end
 
diff --git a/src/string/builder.cr b/src/string/builder.cr
index c7dc2adf7867..bd6f94b8f15c 100644
--- a/src/string/builder.cr
+++ b/src/string/builder.cr
@@ -6,7 +6,7 @@ require "io"
 class String::Builder < IO
   getter bytesize : Int32
   getter capacity : Int32
-  getter buffer : Pointer(UInt8)
+  @buffer : Pointer(UInt8)
 
   def initialize(capacity : Int = 64)
     String.check_capacity_in_bounds(capacity)
diff --git a/src/uri.cr b/src/uri.cr
index 4cdca7378f9e..e60a807ef36b 100644
--- a/src/uri.cr
+++ b/src/uri.cr
@@ -502,19 +502,6 @@ class URI
     end
   end
 
-  # Parses `raw_url` into an URI. The `raw_url` may be relative or absolute.
-  #
-  # ```
-  # require "uri"
-  #
-  # uri = URI.parse("http://crystal-lang.org") # => #<URI:0x1068a7e40 @scheme="http", @host="crystal-lang.org", ... >
-  # uri.scheme                                 # => "http"
-  # uri.host                                   # => "crystal-lang.org"
-  # ```
-  def self.parse(raw_url : String) : URI
-    URI::Parser.new(raw_url).run.uri
-  end
-
   # [RFC 3986 6.2.2.3](https://tools.ietf.org/html/rfc3986#section-5.2.4)
   private def remove_dot_segments(path : String)
     result = [] of String
diff --git a/src/uuid.cr b/src/uuid.cr
index f9596b790a09..7e7c36e70993 100644
--- a/src/uuid.cr
+++ b/src/uuid.cr
@@ -30,7 +30,7 @@ struct UUID
     V5 = 5
   end
 
-  protected getter bytes : StaticArray(UInt8, 16)
+  @bytes : StaticArray(UInt8, 16)
 
   # Generates UUID from *bytes*, applying *version* and *variant* to the UUID if
   # present.
diff --git a/src/xml/node.cr b/src/xml/node.cr
index 828ff4736804..6a4bca8d79b8 100644
--- a/src/xml/node.cr
+++ b/src/xml/node.cr
@@ -11,11 +11,6 @@ struct XML::Node
     initialize(node.as(LibXML::Node*))
   end
 
-  # ditto
-  def initialize(node : LibXML::Doc*)
-    initialize(node.as(LibXML::Node*))
-  end
-
   # ditto
   def initialize(@node : LibXML::Node*)
   end