Fix bug related to empty expressions

Update other specs to use new format

spec/compiler/crystal/tools/expand_spec.cr

@@ -157,7 +157,7 @@ describe "expand" do
     {% end %}
     CRYSTAL
 
-    assert_expand_simple code, "1\n2\n3\n"
+    assert_expand_simple code, "1\n\n2\n\n3\n"
   end
 
   it "expands macro control {% for %} with cursor inside it" do
@@ -167,7 +167,7 @@ describe "expand" do
     {% end %}
     CRYSTAL
 
-    assert_expand_simple code, "1\n2\n3\n"
+    assert_expand_simple code, "1\n\n2\n\n3\n"
   end
 
   it "expands macro control {% for %} with cursor at end of it" do
@@ -177,7 +177,7 @@ describe "expand" do
     ‸{% end %}
     CRYSTAL
 
-    assert_expand_simple code, "1\n2\n3\n"
+    assert_expand_simple code, "1\n\n2\n\n3\n"
   end
 
   it "expands macro control {% for %} with indent" do
@@ -195,7 +195,7 @@ describe "expand" do
     {% end %}
     CRYSTAL
 
-    assert_expand_simple code, original: original, expanded: "1\n2\n3\n"
+    assert_expand_simple code, original: original, expanded: "1\n\n2\n\n3\n"
   end
 
   it "expands simple macro" do
@@ -258,7 +258,7 @@ describe "expand" do
     ‸foo
     CRYSTAL
 
-    assert_expand_simple code, original: "foo", expanded: %("if true"\n"1"\n"2"\n"3"\n)
+    assert_expand_simple code, original: "foo", expanded: %("if true"\n\n\n"1"\n\n"2"\n\n"3"\n)
   end
 
   it "expands macros with 2 level" do
@@ -615,6 +615,7 @@ describe "expand" do
     def hello_str
       "hello"
     end
+
     # symbol of hello
     def hello_sym
       :hello

spec/compiler/semantic/restrictions_augmenter_spec.cr

@@ -78,7 +78,9 @@ describe "Semantic: restrictions augmenter" do
           class Baz
           end
         end
+
         @x : Bar::Baz
+
         def initialize(value : ::Foo::Bar::Baz)
           @x = value
         end
@@ -110,7 +112,9 @@ describe "Semantic: restrictions augmenter" do
           class Baz
           end
         end
+
         @x : Bar::Baz
+
         def initialize(value : Bar::Baz)
           @x = value
         end
@@ -400,8 +404,10 @@ describe "Semantic: restrictions augmenter" do
       macro foo
         {{ yield }}
       end
+
       class Foo
       end
+
       class Bar
         @x : Foo
         def initialize(value : ::Foo)

src/compiler/crystal/syntax/to_s.cr

@@ -236,11 +236,11 @@ module Crystal
       if @inside_macro > 0
         node.expressions.each &.accept self
       else
-        last_node = node.expressions.first
+        last_node = nil
 
         node.expressions.each_with_index do |exp, i|
           unless exp.nop?
-            self.write_extra_newlines last_node.end_location, exp.location do
+            self.write_extra_newlines((last_node || exp).end_location, exp.location) do
               append_indent unless node.keyword.paren? && i == 0
               exp.accept self
               newline unless node.keyword.paren? && i == node.expressions.size - 1