diff --git a/src/errors.cr b/src/errors.cr
index 4ec6cd5c..51670520 100644
--- a/src/errors.cr
+++ b/src/errors.cr
@@ -35,15 +35,15 @@ module Shards
     end
 
     def to_s(io)
-      io.puts "in #{ filename }:#{ line_number }: #{ self.class.name }: #{ message }"
+      io.puts "in #{ filename }: #{ message }"
       io.puts
 
       lines = input.split('\n')
-      from = line_number - 2
+      from = line_number - 3
       from = 0 if from < 0
 
-      lines[from .. line_number].each_with_index do |line, i|
-        io.puts "  #{ i + 1 }. #{ line }"
+      lines[from ... line_number].each_with_index do |line, i|
+        io.puts "  #{ from + i + 1 }. #{ line }"
       end
 
       arrow = String.build do |s|
diff --git a/src/lock.cr b/src/lock.cr
index 9d65c3a4..3cf98954 100644
--- a/src/lock.cr
+++ b/src/lock.cr
@@ -27,7 +27,7 @@ module Shards
                 dependencies << Dependency.new(pull)
               end
             else
-              pull.raise "no such attribute #{key} in lock version 1.0"
+              pull.raise "No such attribute #{key} in lock version 1.0"
             end
           end
         end
diff --git a/src/resolvers/git.cr b/src/resolvers/git.cr
index 7b616d07..2649157c 100644
--- a/src/resolvers/git.cr
+++ b/src/resolvers/git.cr
@@ -214,7 +214,7 @@ module Shards
 
     private def run(command, path = local_path, capture = false)
       unless GitResolver.has_git_command?
-        raise Error.new("Error: missing git command line tool. Please install Git first!")
+        raise Error.new("Error missing git command line tool. Please install Git first!")
       end
 
       # Shards.logger.debug { "cd #{path}" }
@@ -233,7 +233,7 @@ module Shards
           if str.starts_with?("error: ") && (idx = str.index('\n'))
             message = str[7 ... idx]
           end
-          raise Error.new("git command failed: #{ command } (#{ message }). Maybe a commit, branch or file doesn't exist?")
+          raise Error.new("Failed #{ command } (#{ message }). Maybe a commit, branch or file doesn't exist?")
         end
       end
     end
diff --git a/src/resolvers/resolver.cr b/src/resolvers/resolver.cr
index bba328cd..44686085 100644
--- a/src/resolvers/resolver.cr
+++ b/src/resolvers/resolver.cr
@@ -92,7 +92,7 @@ module Shards
   def self.find_resolver(dependency, update_cache = true)
     @@resolvers[dependency.name] ||= begin
       klass = get_resolver_class(dependency.keys)
-      raise Error.new("can't resolve dependency #{dependency.name} (unsupported resolver)") unless klass
+      raise Error.new("Failed can't resolve dependency #{dependency.name} (unsupported resolver)") unless klass
       klass.new(dependency, update_cache: update_cache)
     end
   end
diff --git a/src/spec.cr b/src/spec.cr
index ba859585..53c1e12b 100644
--- a/src/spec.cr
+++ b/src/spec.cr
@@ -30,13 +30,15 @@ module Shards
 
       def self.new(pull : YAML::PullParser)
         name = pull.read_scalar
+
+        line, column = pull.location
         version = pull.read_scalar.strip if pull.kind.scalar?
 
-        if version && !version.empty?
-          new(name, version)
-        else
-          raise Error.new("library version of #{name} can't be empty, use * for any version.")
+        if !version || version.try(&.empty?)
+          pull.raise "library version for #{name} can't be empty, use * for any version", line, column
         end
+
+        new(name, version)
       end
 
       def initialize(@soname, @version)
@@ -71,6 +73,8 @@ module Shards
     # :nodoc:
     def initialize(pull : YAML::PullParser, validate = false)
       pull.each_in_mapping do
+        line, column = pull.location
+
         case key = pull.read_scalar
         when "name"
           @name = pull.read_scalar
@@ -108,7 +112,7 @@ module Shards
           end
         else
           if validate
-            pull.raise "unknown attribute: #{key}"
+            pull.raise "unknown attribute: #{key}", line, column
           else
             pull.skip
           end