fmt: respect user choice of empty lines between type declarations (#9135)

vlib/v/fmt/fmt.v

@@ -334,6 +334,10 @@ fn (f Fmt) should_insert_newline_before_node(node ast.Node, prev_node ast.Node)
 		if prev_stmt is ast.StructDecl {
 			return true
 		}
+		// Empty line after an block of type declarations
+		if prev_stmt is ast.TypeDecl && stmt !is ast.TypeDecl {
+			return true
+		}
 		// Imports are handled special hence they are ignored here
 		if stmt is ast.Import || prev_stmt is ast.Import {
 			return false
@@ -481,6 +485,7 @@ pub fn (mut f Fmt) type_decl(node ast.TypeDecl) {
 		ast.FnTypeDecl { f.fn_type_decl(node) }
 		ast.SumTypeDecl { f.sum_type_decl(node) }
 	}
+	f.writeln('')
 }
 
 pub fn (mut f Fmt) alias_type_decl(node ast.AliasTypeDecl) {
@@ -491,7 +496,6 @@ pub fn (mut f Fmt) alias_type_decl(node ast.AliasTypeDecl) {
 	f.write('type $node.name = $ptype')
 
 	f.comments(node.comments, has_nl: false)
-	f.writeln('\n')
 }
 
 pub fn (mut f Fmt) fn_type_decl(node ast.FnTypeDecl) {
@@ -539,7 +543,6 @@ pub fn (mut f Fmt) fn_type_decl(node ast.FnTypeDecl) {
 	}
 
 	f.comments(node.comments, has_nl: false)
-	f.writeln('\n')
 }
 
 pub fn (mut f Fmt) sum_type_decl(node ast.SumTypeDecl) {
@@ -563,7 +566,6 @@ pub fn (mut f Fmt) sum_type_decl(node ast.SumTypeDecl) {
 	}
 
 	f.comments(node.comments, has_nl: false)
-	f.writeln('\n')
 }
 
 [inline]

vlib/v/fmt/tests/empty_lines_expected.vv

@@ -1,3 +1,6 @@
+type MyInt = int
+type EmptyLineAfterLastType = fn () int
+
 struct EmptyLineAfterStructs {}
 
 fn empty_line_after_functions() {}

vlib/v/fmt/tests/empty_lines_input.vv

@@ -1,3 +1,5 @@
+type MyInt = int
+type EmptyLineAfterLastType = fn() int
 struct EmptyLineAfterStructs {}
 fn empty_line_after_functions() {}
 fn squash_multiple_empty_lines() {

vlib/v/fmt/tests/empty_lines_keep.vv

@@ -1,3 +1,9 @@
+// Keep empty lines between types
+type Expr = IfExpr | IntegerLiteral
+
+type Node2 = Expr | string
+type MyInt = int
+
 // Keep empty lines in const blocks
 const (
 	_ = SomeStruct{

vlib/v/fmt/tests/types_expected.vv

@@ -1,6 +1,5 @@
 // Sumtype
 type FooBar = Bar | Foo
-
 pub type PublicBar = Bar | Foo | FooBar
 
 type Uint = byte | u16 | u32 | u64 // This should stay on the same line
@@ -15,7 +14,6 @@ pub type Abc = f32
 // Fn type decl
 
 type EmptyFn = fn ()
-
 type OneArgFn = fn (i int)
 
 type TwoDiffArgs = fn (i int, s string) bool