Improve errors for invalid use of [...]type.

From-SVN: r178921

gcc/go/gofrontend/expressions.cc

@@ -11789,7 +11789,7 @@ Array_construction_expression::do_check_types(Gogo*)
     }
 
   Expression* length = at->length();
-  if (length != NULL)
+  if (length != NULL && !length->is_error_expression())
     {
       mpz_t val;
       mpz_init(val);

gcc/go/gofrontend/parse.cc

@@ -2761,8 +2761,21 @@ Parse::primary_expr(bool may_be_sink, bool may_be_composite_lit,
 	  else
 	    this->advance_token();
 	  if (expr->is_error_expression())
-	    return expr;
-	  ret = Expression::make_cast(ret->type(), expr, loc);
+	    ret = expr;
+	  else
+	    {
+	      Type* t = ret->type();
+	      if (t->classification() == Type::TYPE_ARRAY
+		  && t->array_type()->length() != NULL
+		  && t->array_type()->length()->is_nil_expression())
+		{
+		  error_at(ret->location(),
+			   "invalid use of %<...%> in type conversion");
+		  ret = Expression::make_error(loc);
+		}
+	      else
+		ret = Expression::make_cast(t, expr, loc);
+	    }
 	}
     }
 

gcc/testsuite/go.test/test/ddd1.go

@@ -15,7 +15,7 @@ var (
 	_ = sum()
 	_ = sum(1.0, 2.0)
 	_ = sum(1.5)      // ERROR "integer"
-	_ = sum("hello")  // ERROR "convert|incompatible"
+	_ = sum("hello")  // ERROR "string.*as type int|incompatible"
 	_ = sum([]int{1}) // ERROR "slice literal.*as type int|incompatible"
 )
 
@@ -43,4 +43,7 @@ func bad(args ...int) {
 	var x int
 	_ = unsafe.Pointer(&x...)	// ERROR "[.][.][.]"
 	_ = unsafe.Sizeof(x...)	// ERROR "[.][.][.]"
+	_ = [...]byte("foo") // ERROR "[.][.][.]"
+	_ = [...][...]int{{1,2,3},{4,5,6}}	// ERROR "[.][.][.]"
 }
+