From a456c21249b80f63e24a8a5440808727a3d8efdc Mon Sep 17 00:00:00 2001
From: Joe Conigliaro <joe.conigliaro@gmail.com>
Date: Thu, 19 Mar 2020 19:40:21 +1100
Subject: [PATCH] gen: cgen sum cast in struct init

---
 vlib/v/ast/ast.v         | 11 +++++++----
 vlib/v/checker/checker.v |  6 ++++--
 vlib/v/gen/cgen.v        | 14 +++++++-------
 3 files changed, 18 insertions(+), 13 deletions(-)

diff --git a/vlib/v/ast/ast.v b/vlib/v/ast/ast.v
index c512f01323..72206e9385 100644
--- a/vlib/v/ast/ast.v
+++ b/vlib/v/ast/ast.v
@@ -112,10 +112,13 @@ pub:
 
 pub struct StructInit {
 pub:
-	pos    token.Position
-	typ    table.Type
-	fields []string
-	exprs  []Expr
+	pos            token.Position
+	typ            table.Type
+	fields         []string
+	exprs          []Expr
+mut:
+	expr_types     []table.Type
+	expected_types []table.Type
 }
 
 // import statement
diff --git a/vlib/v/checker/checker.v b/vlib/v/checker/checker.v
index 12e18b47ef..9cc2229257 100644
--- a/vlib/v/checker/checker.v
+++ b/vlib/v/checker/checker.v
@@ -71,7 +71,7 @@ pub fn (c mut Checker) check_files(ast_files []ast.File) {
 	}
 }
 
-pub fn (c mut Checker) check_struct_init(struct_init ast.StructInit) table.Type {
+pub fn (c mut Checker) struct_init(struct_init mut ast.StructInit) table.Type {
 	// typ := c.table.find_type(struct_init.typ.typ.name) or {
 	// c.error('unknown struct: $struct_init.typ.typ.name', struct_init.pos)
 	// panic('')
@@ -117,6 +117,8 @@ pub fn (c mut Checker) check_struct_init(struct_init ast.StructInit) table.Type
 				if !c.table.check(expr_type, field.typ) {
 					c.error('cannot assign `$expr_type_sym.name` as `$field_type_sym.name` for field `$field.name`', struct_init.pos)
 				}
+				struct_init.expr_types << expr_type
+				struct_init.expected_types << field.typ
 			}
 		}
 		else {}
@@ -726,7 +728,7 @@ pub fn (c mut Checker) expr(node ast.Expr) table.Type {
 			return table.string_type
 		}
 		ast.StructInit {
-			return c.check_struct_init(it)
+			return c.struct_init(mut it)
 		}
 		ast.Type {
 			return it.typ
diff --git a/vlib/v/gen/cgen.v b/vlib/v/gen/cgen.v
index 55be43404e..89053c7ea3 100644
--- a/vlib/v/gen/cgen.v
+++ b/vlib/v/gen/cgen.v
@@ -345,7 +345,7 @@ fn (g mut Gen) stmt(node ast.Stmt) {
 }
 
 // use instead of expr() when you need to cast to sum type (can add other casts also)
-fn (g mut Gen) expr_with_cast(got_type table.Type, exp_type table.Type, expr ast.Expr) {
+fn (g mut Gen) expr_with_cast(expr ast.Expr, got_type table.Type, exp_type table.Type) {
 	// cast to sum type
 	if exp_type != table.void_type && exp_type != 0 && got_type != 0 {
 		exp_sym := g.table.get_type_symbol(exp_type)
@@ -432,7 +432,7 @@ fn (g mut Gen) gen_assign_stmt(assign_stmt ast.AssignStmt) {
 				if !is_fixed_array_init {
 					g.write(' = ')
 					if !is_decl {
-						g.expr_with_cast(assign_stmt.left_types[i], ident_var_info.typ, val)
+						g.expr_with_cast(val, assign_stmt.left_types[i], ident_var_info.typ)
 					}
 					else {
 						g.expr(val)
@@ -603,7 +603,7 @@ fn (g mut Gen) expr(node ast.Expr) {
 					g.write(', ')
 				}
 				g.is_assign_expr = false
-				g.expr_with_cast(it.right_type, it.left_type, it.val)
+				g.expr_with_cast(it.val, it.right_type, it.left_type)
 				if g.is_array_set {
 					g.write(' })')
 					g.is_array_set = false
@@ -854,7 +854,7 @@ fn (g mut Gen) expr(node ast.Expr) {
 			}
 			for i, field in it.fields {
 				g.write('\t.$field = ')
-				g.expr(it.exprs[i])
+				g.expr_with_cast(it.exprs[i], it.expr_types[i], it.expected_types[i])
 				g.writeln(', ')
 			}
 			if it.fields.len == 0 {
@@ -964,7 +964,7 @@ fn (g mut Gen) infix_expr(node ast.InfixExpr) {
 		if right_sym.kind == .array {
 			// push an array => PUSH_MANY
 			g.write('_PUSH_MANY(&')
-			g.expr_with_cast(node.right_type, node.left_type, node.left)
+			g.expr_with_cast(node.left, node.right_type, node.left_type)
 			g.write(', (')
 			g.expr(node.right)
 			styp := g.typ(node.left_type)
@@ -976,7 +976,7 @@ fn (g mut Gen) infix_expr(node ast.InfixExpr) {
 			elem_type_str := g.typ(info.elem_type)
 			// g.write('array_push(&')
 			g.write('_PUSH(&')
-			g.expr_with_cast(node.right_type, info.elem_type, node.left)
+			g.expr_with_cast(node.left, node.right_type, info.elem_type)
 			g.write(', (')
 			g.expr(node.right)
 			g.write('), $tmp, $elem_type_str)')
@@ -1328,7 +1328,7 @@ fn (g mut Gen) return_statement(it ast.Return) {
 			// Automatic Dereference
 			g.write('*')
 		}
-		g.expr_with_cast(it.types[0], g.fn_decl.return_type, it.exprs[0])
+		g.expr_with_cast(it.exprs[0], it.types[0], g.fn_decl.return_type)
 	}
 	g.writeln(';')
 }