From 0bc80951e376a3e5c1fae417610fdcb4beb81575 Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@vlang.io>
Date: Tue, 11 May 2021 10:28:11 +0300
Subject: [PATCH] checker: fix `T is int`

---
 vlib/v/checker/checker.v | 3 ++-
 vlib/v/gen/c/comptime.v  | 3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/vlib/v/checker/checker.v b/vlib/v/checker/checker.v
index 2f4287f35d..5ee6b954af 100644
--- a/vlib/v/checker/checker.v
+++ b/vlib/v/checker/checker.v
@@ -5982,7 +5982,8 @@ fn (mut c Checker) comp_if_branch(cond ast.Expr, pos token.Position) bool {
 						type_node := cond.right as ast.TypeNode
 						sym := c.table.get_type_symbol(type_node.typ)
 						if sym.kind != .interface_ {
-							c.error('`$sym.name` is not an interface', cond.right.position())
+							c.expr(cond.left)
+							// c.error('`$sym.name` is not an interface', cond.right.position())
 						}
 						return false
 					} else if cond.left is ast.SelectorExpr || cond.left is ast.TypeNode {
diff --git a/vlib/v/gen/c/comptime.v b/vlib/v/gen/c/comptime.v
index ff8a1ca2ec..1bc8c34d0a 100644
--- a/vlib/v/gen/c/comptime.v
+++ b/vlib/v/gen/c/comptime.v
@@ -319,7 +319,8 @@ fn (mut g Gen) comp_if_cond(cond ast.Expr) bool {
 					got_type := (cond.right as ast.TypeNode).typ
 					// Handle `$if x is Interface {`
 					// mut matches_interface := 'false'
-					if left is ast.TypeNode && cond.right is ast.TypeNode {
+					if left is ast.TypeNode && cond.right is ast.TypeNode
+						&& g.table.get_type_symbol(got_type).kind == .interface_ {
 						// `$if Foo is Interface {`
 						interface_sym := g.table.get_type_symbol(got_type)
 						if interface_sym.info is ast.Interface {