From 966e1f7b5ae375380f2e4c2a52fdea82ca3c01dd Mon Sep 17 00:00:00 2001
From: Michael Forney <mforney@mforney.org>
Date: Mon, 15 Apr 2019 21:57:48 -0700
Subject: expr: Check operand to '&' operator

---
 expr.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/expr.c b/expr.c
index 4a746bc..f9f1703 100644
--- a/expr.c
+++ b/expr.c
@@ -81,6 +81,14 @@ mkunaryexpr(enum tokenkind op, struct expr *base)
 			base->decayed = false;
 			return base;
 		}
+		/*
+		Allow struct and union types even if they are not lvalues,
+		since we take their address when compiling member access.
+		*/
+		if (!base->lvalue && base->type->kind != TYPEFUNC && base->type->kind != TYPESTRUCT && base->type->kind != TYPEUNION)
+			error(&tok.loc, "'&' operand is not an lvalue or function designator");
+		if (base->kind == EXPRBITFIELD)
+			error(&tok.loc, "cannot take address of bit-field");
 		expr = mkexpr(EXPRUNARY, mkpointertype(base->type, base->qual));
 		expr->unary.op = op;
 		expr->unary.base = base;
-- 
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