Fix missing check on foreach indexing.

src/compiler/sema_stmts.c

@@ -1242,7 +1242,13 @@ static inline bool sema_analyse_foreach_stmt(SemaContext *context, Ast *statemen
 			return false;
 		}
 		index_macro = value_by_ref ? by_ref : by_val;
+		assert(index_macro);
 		index_type = index_macro->func_decl.signature.params[1]->type;
+		if (!type_is_integer(index_type))
+		{
+			SEMA_ERROR(enumerator, "Only integer indexed types may be used with foreach.");
+			return false;
+		}
 		TypeInfoId rtype = index_macro->func_decl.signature.rtype;
 		value_type = rtype ? type_infoptr(rtype)->type : NULL;
 	}

test/test_suite/statements/foreach_wrong_index.c3

@@ -0,0 +1,27 @@
+import std::io;
+
+struct Foo
+{
+    int[3] elements;
+}
+
+fn int Foo.at(Foo *vector, float index) @operator([])
+{
+    return 1;
+}
+
+fn int Foo.len(Foo *vector) @operator(len)
+{
+    return 3;
+}
+
+fn void main()
+{
+
+    Foo f;
+    io::printfln("%s", f[12.2]);
+    foreach (int i, value : f) // #error: Only integer
+    {
+        io::printfln("v[%s] = %s", i, value);
+    }
+}

test/test_suite2/statements/foreach_wrong_index.c3

@@ -0,0 +1,27 @@
+import std::io;
+
+struct Foo
+{
+    int[3] elements;
+}
+
+fn int Foo.at(Foo *vector, float index) @operator([])
+{
+    return 1;
+}
+
+fn int Foo.len(Foo *vector) @operator(len)
+{
+    return 3;
+}
+
+fn void main()
+{
+
+    Foo f;
+    io::printfln("%s", f[12.2]);
+    foreach (int i, value : f) // #error: Only integer
+    {
+        io::printfln("v[%s] = %s", i, value);
+    }
+}