cgen: fix match expr multiline error

* cgen: fix match expr multiline error
* Support for multiple statements in the else part of the match.
* Add a test for the match expression with multiple statements.

vlib/v/gen/cgen.v

@@ -324,11 +324,17 @@ pub fn (g mut Gen) reset_tmp_count() {
 
 fn (g mut Gen) stmts(stmts []ast.Stmt) {
 	g.indent++
-	for stmt in stmts {
+	if g.inside_ternary {
+		g.write(' ( ')
+	}
+	for i, stmt in stmts {
 		g.stmt(stmt)
-		// if !g.inside_ternary {
-		// g.writeln('')
-		// }
+		if g.inside_ternary && i < stmts.len - 1 {
+			g.write(', ')
+		}
+	}
+	if g.inside_ternary {
+		g.write(' ) ')
 	}
 	g.indent--
 }

vlib/v/tests/match_expression_for_types_test.v

@@ -0,0 +1,66 @@
+
+type SumType = int | string
+
+fn s2s(s SumType) SumType { return s }
+
+fn test_match_expression_on_sumtype_ordinary_branch(){
+	// tests whether an ordinary branch supports multiple statements,
+	// followed by a default expression
+	mut c := 0
+	s := s2s('abc')
+	res := match s {
+		string {
+			c = 1
+			eprintln('hi')
+			'a string'
+		}else{
+			'unknown'
+		}
+	}
+	assert res == 'a string'
+	assert c == 1
+}
+
+
+fn test_match_expression_on_sumtype_else(){
+	// tests whether else branches support multiple statements,
+	// when the other branches are simple default expressions
+	mut c := 0
+	s := s2s(123)
+	res := match s {
+		string {
+			'a string'
+		}else{
+			c = 3
+			eprintln('hi')
+			'unknown'
+		}
+	}
+	assert res == 'unknown'
+	assert c == 3
+}
+
+fn test_match_expression_on_sumtype_full(){
+	// tests whether all branches can have multiple statements,
+	// followed by a default expression
+	mut c := 0
+	s := s2s(123)
+	res := match s {
+		int {
+			c = 1
+			eprintln('hi')
+			'an integer'
+		}
+		string {
+			c = 2
+			eprintln('hi')
+			'a string'
+		}else{
+			c = 3
+			eprintln('hi')
+			'unknown'
+		}
+	}
+	assert res == 'an integer'
+	assert c == 1
+}