diff --git a/vlib/v/ast/ast.v b/vlib/v/ast/ast.v
index 5710f0cb38..1a8b70bbb2 100644
--- a/vlib/v/ast/ast.v
+++ b/vlib/v/ast/ast.v
@@ -607,6 +607,7 @@ mut:
 pub struct AssertStmt {
 pub:
 	expr Expr
+	pos  token.Position
 }
 
 // `if [x := opt()] {`
diff --git a/vlib/v/gen/cgen.v b/vlib/v/gen/cgen.v
index 1cb9f7267c..184b8ba0e7 100644
--- a/vlib/v/gen/cgen.v
+++ b/vlib/v/gen/cgen.v
@@ -274,11 +274,10 @@ fn (g mut Gen) stmt(node ast.Stmt) {
 			g.expr(it.expr)
 			g.writeln(')) {')
 			g.writeln('g_test_fails++;')
-			g.writeln('puts("FAILED assertion");')
-			g.writeln('puts("function: $g.fn_decl.name");')
+			g.writeln('puts("FAILED $g.fn_decl.name $it.pos.line_nr");')
 			g.writeln('} else {')
 			g.writeln('g_test_oks++;')
-			g.writeln('puts("OK $g.fn_decl.name");')
+			// g.writeln('puts("OK $g.fn_decl.name");')
 			g.writeln('}')
 		}
 		ast.AssignStmt {
@@ -1216,12 +1215,16 @@ fn (g mut Gen) infix_expr(node ast.InfixExpr) {
 		}
 	}
 	else {
-		// if node.op == .dot {
-		// println('!! dot')
-		// }
+		need_par := node.op == .amp // `x & y == 0` => `(x & y) == 0` in C
+		if need_par {
+			g.write('(')
+		}
 		g.expr(node.left)
 		g.write(' $node.op.str() ')
 		g.expr(node.right)
+		if need_par {
+			g.write(')')
+		}
 	}
 }
 
diff --git a/vlib/v/parser/parser.v b/vlib/v/parser/parser.v
index d25571cc84..aecd8f11ff 100644
--- a/vlib/v/parser/parser.v
+++ b/vlib/v/parser/parser.v
@@ -346,6 +346,7 @@ pub fn (p mut Parser) stmt() ast.Stmt {
 			expr := p.expr(0)
 			return ast.AssertStmt{
 				expr: expr
+				pos: p.tok.position()
 			}
 		}
 		.key_mut {