fmt: enable shared return types (#8614)

vlib/v/ast/str.v

@@ -26,7 +26,8 @@ pub fn (node &FnDecl) stringify(t &table.Table, cur_mod string, m2a map[string]s
 	}
 	mut receiver := ''
 	if node.is_method {
-		mut styp := util.no_cur_mod(t.type_to_code(node.receiver.typ), cur_mod)
+		mut styp := util.no_cur_mod(t.type_to_code(node.receiver.typ.clear_flag(.shared_f)),
+			cur_mod)
 		m := if node.rec_mut { node.receiver.typ.share().str() + ' ' } else { '' }
 		if node.rec_mut {
 			styp = styp[1..] // remove &
@@ -88,7 +89,7 @@ pub fn (node &FnDecl) stringify(t &table.Table, cur_mod string, m2a map[string]s
 			f.write(arg.typ.share().str() + ' ')
 		}
 		f.write(arg.name)
-		mut s := t.type_to_str(arg.typ)
+		mut s := t.type_to_str(arg.typ.clear_flag(.shared_f))
 		if arg.is_mut {
 			// f.write(' mut')
 			if s.starts_with('&') {

vlib/v/checker/tests/shared_type_mismatch.out

@@ -0,0 +1,7 @@
+vlib/v/checker/tests/shared_type_mismatch.vv:13:3: error: wrong return type `St` in the `or {}` block, expected `shared St`
+   11 | fn test_shared_opt_bad() {
+   12 |     shared yy := f() or {
+   13 |         St{ x: 37.5 }
+      |         ~~~~~~~~~~~~~
+   14 |     }
+   15 |     rlock yy {

vlib/v/checker/tests/shared_type_mismatch.vv

@@ -0,0 +1,18 @@
+struct St {
+mut:
+	x f64
+}
+
+fn f() ?shared St {
+	shared x := St{ x: 12.75 }
+	return x
+}
+
+fn test_shared_opt_bad() {
+	shared yy := f() or {
+		St{ x: 37.5 }
+	}
+	rlock yy {
+	    println(yy.x)
+	}
+}

vlib/v/fmt/tests/shared_expected.vv

@@ -17,6 +17,34 @@ fn (shared x St) f(shared z St) {
 	}
 }
 
+fn g() shared St {
+	shared x := St{
+		a: 12
+	}
+	return x
+}
+
+fn h() ?shared St {
+	return error('no value')
+}
+
+fn k() {
+	shared x := g()
+	shared y := h() or {
+		shared f := St{}
+		f
+	}
+	shared z := h() ?
+	shared p := v
+	v := rlock z {
+		z.a
+	}
+	lock y, z; rlock x, p {
+		z.a = x.a + y.a
+	}
+	println(v)
+}
+
 const (
 	reads_per_thread = 30
 	read_threads     = 10

vlib/v/fmt/tests/shared_input.vv

@@ -18,6 +18,30 @@ fn (shared x St) f(shared z St) {
 	}
 }
 
+fn g() shared St {
+shared  x := St{a: 12 }
+		return   x
+}
+
+fn h() ?shared St {
+    return error('no value')
+}
+
+fn k() {
+  shared  x := g()
+  shared y := h() or {
+      shared f := St{}
+	  f
+	 }
+	 shared z := h() ?
+	 shared p := v
+	 v := rlock  z {  z.a }
+	 rlock x; lock y, z; rlock p {
+	  z.a = x.a + y.a
+	  }
+	 println(v)
+}
+
 const (
 	reads_per_thread = 30
 	read_threads     = 10

vlib/v/table/types.v

@@ -846,7 +846,11 @@ pub fn (mytable &Table) type_to_str_using_aliases(t Type, import_aliases map[str
 			res = mytable.shorten_user_defined_typenames(res, import_aliases)
 		}
 	}
-	nr_muls := t.nr_muls()
+	mut nr_muls := t.nr_muls()
+	if t.has_flag(.shared_f) {
+		nr_muls--
+		res = 'shared ' + res
+	}
 	if nr_muls > 0 {
 		res = strings.repeat(`&`, nr_muls) + res
 	}