checker: fix checker enum infix error

vlib/v/ast/ast.v

@@ -502,7 +502,8 @@ mut:
 pub struct EnumField {
 	name     string
 	pos      token.Position
-	exprs []Expr
+	expr     Expr
+	has_expr bool
 }
 
 pub struct EnumDecl {

vlib/v/checker/checker.v

@@ -562,12 +562,12 @@ pub fn (c mut Checker) return_stmt(return_stmt mut ast.Return) {
 
 pub fn (c mut Checker) enum_decl(decl ast.EnumDecl) {
 	for field in decl.fields {
-		for expr in field.exprs {
-			match expr {
+		if field.has_expr {
+			match field.expr {
 				ast.IntegerLiteral {}
 				ast.PrefixExpr {}
 				else {
-					mut pos := expr_pos(expr)
+					pos := expr_pos(field.expr)
 					if pos.pos == 0 {
 						pos = field.pos
 					}
@@ -1064,7 +1064,18 @@ fn expr_pos(node ast.Expr) token.Position {
 		ast.IfExpr { return it.pos }
 		// ast.IfGuardExpr { }
 		ast.IndexExpr { return it.pos }
-		ast.InfixExpr { return it.pos }
+		ast.InfixExpr {
+			left_pos := expr_pos(it.left)
+			right_pos := expr_pos(it.right)
+			if left_pos.pos == 0 || right_pos.pos == 0 {
+				return it.pos
+			}
+			return token.Position{
+				line_nr: it.pos.line_nr
+				pos: left_pos.pos
+				len: right_pos.pos - left_pos.pos + right_pos.len
+			}
+		}
 		ast.IntegerLiteral { return it.pos }
 		ast.MapInit { return it.pos }
 		ast.MatchExpr { return it.pos }

vlib/v/checker/tests/inout/enum_err.out

@@ -2,5 +2,12 @@ vlib/v/checker/tests/inout/enum_err.v:2:13: error: default value for enum has to
     1| enum Color {
     2|     green = 'green',
                    ~~~~~~~
-    3|     blue,
-    4| }
+    3|     yellow = 1+1,
+    4|     blue,
+vlib/v/checker/tests/inout/enum_err.v:3:14: error: default value for enum has to be an integer
+    1| enum Color {
+    2|     green = 'green',
+    3|     yellow = 1+1,
+                    ~~~
+    4|     blue,
+    5| }

vlib/v/checker/tests/inout/enum_err.vv

@@ -1,4 +1,5 @@
 enum Color {
     green = 'green',
+    yellow = 1+1,
     blue,
 }

vlib/v/fmt/fmt.v

@@ -210,11 +210,9 @@ fn (f mut Fmt) stmt(node ast.Stmt) {
 			f.writeln('enum $name {')
 			for field in it.fields {
 				f.write('\t$field.name')
-				if field.exprs.len > 0 {
+				if field.has_expr {
 					f.write(' = ')
-					for expr in field.exprs {
-						f.expr(expr)
-					}
+					f.expr(field.expr)
 					f.writeln(',')
 				} else {
 					f.writeln('')

vlib/v/gen/cgen.v

@@ -367,12 +367,10 @@ fn (g mut Gen) stmt(node ast.Stmt) {
 			g.typedefs.writeln('typedef enum {')
 			for field in it.fields {
 				g.typedefs.write('\t${enum_name}_$field.name')
-				if field.exprs.len > 0 {
+				if field.has_expr {
 					g.typedefs.write(' = ')
-				}
-				for expr in field.exprs {
 					pos := g.out.len
-					g.expr(expr)
+					g.expr(field.expr)
 					expr_str := g.out.after(pos)
 					g.out.go_back(expr_str.len)
 					g.typedefs.write('$expr_str')

vlib/v/parser/parser.v

@@ -843,13 +843,14 @@ pub fn (p mut Parser) expr(precedence int) ast.Expr {
 			// will fudge left shift as it makes it right assoc
 			// `arr << 'a'` | `arr << 'a' + 'b'`
 			tok := p.tok
+			pos :=  tok.position()
 			p.next()
 			right := p.expr(precedence - 1)
 			node = ast.InfixExpr{
 				left: node
 				right: right
 				op: tok.kind
-				pos: tok.position()
+				pos:pos
 			}
 		} else if p.tok.kind.is_infix() {
 			node = p.infix_expr(node)
@@ -1876,13 +1877,15 @@ fn (p mut Parser) enum_decl() ast.EnumDecl {
 		pos := p.tok.position()
 		val := p.check_name()
 		vals << val
-		mut exprs := []ast.Expr
+		mut expr := ast.Expr{}
+		mut has_expr := false
 		// p.warn('enum val $val')
 		if p.tok.kind == .assign {
 			p.next()
-			exprs << p.expr(0)
+			expr = p.expr(0)
+			has_expr = true
 		}
-		fields << ast.EnumField{val, pos, exprs}
+		fields << ast.EnumField{val, pos, expr, has_expr}
 		// Allow commas after enum, helpful for
 		// enum Color {
 		// r,g,b