From f0a23c8d3c3f03ac582e76cd9763352d92b762bb Mon Sep 17 00:00:00 2001
From: yuyi <yuyi98@163.com>
Date: Thu, 24 Nov 2022 18:05:57 +0800
Subject: [PATCH] cgen: fix fn call of sumtype with alias fntype variant
 (#16519)

---
 vlib/v/gen/c/cgen.v                           | 32 +++++++++----------
 vlib/v/gen/c/fn.v                             |  7 ++--
 vlib/v/tests/sumtype_with_alias_fntype_test.v | 21 ++++++++----
 3 files changed, 33 insertions(+), 27 deletions(-)

diff --git a/vlib/v/gen/c/cgen.v b/vlib/v/gen/c/cgen.v
index 9f6d9c75ac..b1a495cb09 100644
--- a/vlib/v/gen/c/cgen.v
+++ b/vlib/v/gen/c/cgen.v
@@ -2281,25 +2281,23 @@ fn (mut g Gen) write_sumtype_casting_fn(fun SumtypeCastingFn) {
 	mut sb := strings.new_builder(128)
 	mut is_anon_fn := false
 	if got_sym.info is ast.FnType {
-		if got_sym.info.is_anon || g.table.known_fn(got_sym.name) {
-			got_name := 'fn ${g.table.fn_type_source_signature(got_sym.info.func)}'
-			got_cname = 'anon_fn_${g.table.fn_type_signature(got_sym.info.func)}'
-			type_idx = g.table.type_idxs[got_name].str()
-			exp_info := exp_sym.info as ast.SumType
-			for variant in exp_info.variants {
-				variant_sym := g.table.sym(variant)
-				if variant_sym.info is ast.FnType {
-					if g.table.fn_type_source_signature(variant_sym.info.func) == g.table.fn_type_source_signature(got_sym.info.func) {
-						got_cname = variant_sym.cname
-						type_idx = variant.idx().str()
-						break
-					}
+		got_name := 'fn ${g.table.fn_type_source_signature(got_sym.info.func)}'
+		got_cname = 'anon_fn_${g.table.fn_type_signature(got_sym.info.func)}'
+		type_idx = g.table.type_idxs[got_name].str()
+		exp_info := exp_sym.info as ast.SumType
+		for variant in exp_info.variants {
+			variant_sym := g.table.sym(variant)
+			if variant_sym.info is ast.FnType {
+				if g.table.fn_type_source_signature(variant_sym.info.func) == g.table.fn_type_source_signature(got_sym.info.func) {
+					got_cname = variant_sym.cname
+					type_idx = variant.idx().str()
+					break
 				}
 			}
-			sb.writeln('static inline ${exp_cname} ${fun.fn_name}(${got_cname} x) {')
-			sb.writeln('\t${got_cname} ptr = x;')
-			is_anon_fn = true
 		}
+		sb.writeln('static inline ${exp_cname} ${fun.fn_name}(${got_cname} x) {')
+		sb.writeln('\t${got_cname} ptr = x;')
+		is_anon_fn = true
 	}
 	if !is_anon_fn {
 		sb.writeln('static inline ${exp_cname} ${fun.fn_name}(${got_cname}* x) {')
@@ -2436,8 +2434,8 @@ fn (mut g Gen) expr_with_cast(expr ast.Expr, got_type_raw ast.Type, expected_typ
 	if got_sym.info is ast.FnType {
 		if got_sym.info.is_anon {
 			got_styp = 'anon_fn_${g.table.fn_type_signature(got_sym.info.func)}'
-			got_is_fn = true
 		}
+		got_is_fn = true
 	}
 	if expected_type != ast.void_type {
 		unwrapped_expected_type := g.unwrap_generic(expected_type)
diff --git a/vlib/v/gen/c/fn.v b/vlib/v/gen/c/fn.v
index 6d6a6e43eb..13756bf3d8 100644
--- a/vlib/v/gen/c/fn.v
+++ b/vlib/v/gen/c/fn.v
@@ -1452,8 +1452,9 @@ fn (mut g Gen) fn_call(node ast.CallExpr) {
 							}
 						}
 						if obj.smartcasts.len > 0 && is_cast_needed {
-							for _ in obj.smartcasts {
-								g.write('(*')
+							for typ in obj.smartcasts {
+								sym := g.table.sym(typ)
+								g.write('(*(${sym.cname})(')
 							}
 							for i, typ in obj.smartcasts {
 								cast_sym := g.table.sym(g.unwrap_generic(typ))
@@ -1471,7 +1472,7 @@ fn (mut g Gen) fn_call(node ast.CallExpr) {
 								} else {
 									g.write('${dot}_${cast_sym.cname}')
 								}
-								g.write(')')
+								g.write('))')
 							}
 							is_fn_var = true
 						} else if obj.is_inherited {
diff --git a/vlib/v/tests/sumtype_with_alias_fntype_test.v b/vlib/v/tests/sumtype_with_alias_fntype_test.v
index 416b5112b8..8136be6e4b 100644
--- a/vlib/v/tests/sumtype_with_alias_fntype_test.v
+++ b/vlib/v/tests/sumtype_with_alias_fntype_test.v
@@ -11,18 +11,25 @@ fn abc(i int) int {
 	return i
 }
 
+// create Myfn
+fn myfnfact() Myfn {
+	return abc
+}
+
+// run fn if exists
 fn run(mmff Maybefnfact) string {
 	match mmff {
-		Myfnfact { return 'yes fn' }
-		None { return 'None fn' }
+		Myfnfact {
+			r := mmff()
+			return 'yes fn: ${r}'
+		}
+		None {
+			return 'None fn'
+		}
 	}
 }
 
 fn test_sumtype_with_alias_fntype() {
-	// create Myfn
-	myfnfact := fn () Myfn {
-		return abc
-	}
 	r1 := main.myfnfact()(1)
 	println(r1)
 	assert r1 == 1
@@ -33,5 +40,5 @@ fn test_sumtype_with_alias_fntype() {
 
 	r3 := run(myfnfact)
 	println(r3)
-	assert r3 == 'yes fn'
+	assert r3 == 'yes fn: fn (int) int'
 }