From: Rico Tzschichholz <ricotz@ubuntu.com>
Date: Tue, 14 Jan 2020 07:36:26 +0000 (+0100)
Subject: codegen: Use result value of assignment rather than its computation
X-Git-Tag: 0.47.3~14
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8dd348ce50260c37fb103f21c5956b7ce63cc2f0;p=thirdparty%2Fvala.git

codegen: Use result value of assignment rather than its computation

An inline assignment of an array-length, like

    int j = --i.length;

resulted in a faulty tranformation

    i_length1 = i_length1 - 1;
    j = i_length1 - 1;

Regression of 80d4bf61e0c3100c839f3fdbcb5218996b6afd5f

Fixes https://gitlab.gnome.org/GNOME/vala/issues/895
---

diff --git a/codegen/valaccodeassignmentmodule.vala b/codegen/valaccodeassignmentmodule.vala
index 617293b0a..fc7e8d6fc 100644
--- a/codegen/valaccodeassignmentmodule.vala
+++ b/codegen/valaccodeassignmentmodule.vala
@@ -83,7 +83,7 @@ public class Vala.CCodeAssignmentModule : CCodeMemberAccessModule {
 		if (assignment.left.value_type is ArrayType && (((ArrayType) assignment.left.value_type).inline_allocated)) {
 			return load_variable (variable, assignment.left.target_value);
 		} else {
-			return assignment.right.target_value;
+			return assignment.left.target_value;
 		}
 	}
 
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 0d4968e75..f7c520de8 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -78,6 +78,7 @@ TESTS = \
 	arrays/fixed-length-concat-invalid.test \
 	arrays/fixed-length-non-const.test \
 	arrays/fixed-length-resize-invalid.test \
+	arrays/length-inline-assignment.vala \
 	arrays/struct-field-length-cname.vala \
 	arrays/incompatible-integer-elements.test \
 	arrays/slice-invalid-start.test \
diff --git a/tests/arrays/length-inline-assignment.vala b/tests/arrays/length-inline-assignment.vala
new file mode 100644
index 000000000..baf33055d
--- /dev/null
+++ b/tests/arrays/length-inline-assignment.vala
@@ -0,0 +1,29 @@
+void main () {
+	{
+		int[] i = { 23, 42 };
+		int j = --i.length;
+		assert (i.length == 1);
+		assert (j == 1);
+		j = ++i.length;
+		assert (i.length == 2);
+		assert (j == 2);
+	}
+	{
+		int[] i = { 23, 42 };
+		int j = (i.length = i.length - 1);
+		assert (i.length == 1);
+		assert (j == 1);
+		j = (i.length = i.length + 1);
+		assert (i.length == 2);
+		assert (j == 2);
+	}
+	{
+		int[] i = { 23, 42 };
+		int j = i.length--;
+		assert (i.length == 1);
+		assert (j == 2);
+		j = i.length++;
+		assert (i.length == 2);
+		assert (j == 1);
+	}
+}