[vala] codegen: Fix copy of fixed arrays when elements require copy

[Luca Bruno <lucabru src gnome org>]

commit 3bb552a242a8dfb4bbd4f5b0ecd01a04081251ad
Author: Luca Bruno <lucabru src gnome org>
Date:   Fri May 20 15:18:55 2011 +0200

    codegen: Fix copy of fixed arrays when elements require copy
    
    Fixes bug 613840.

 codegen/valaccodebasemodule.vala |   12 ++++++++----
 tests/Makefile.am                |    1 +
 tests/objects/bug613840.vala     |    5 +++++
 3 files changed, 14 insertions(+), 4 deletions(-)
---
diff --git a/codegen/valaccodebasemodule.vala b/codegen/valaccodebasemodule.vala
index 9fb3ca3..55ecb69 100644
--- a/codegen/valaccodebasemodule.vala
+++ b/codegen/valaccodebasemodule.vala
@@ -5197,10 +5197,14 @@ public abstract class Vala.CCodeBaseModule : CodeGenerator {
 		if (target_type.value_owned && (!type.value_owned || boxing || unboxing)) {
 			// need to copy value
 			if (requires_copy (target_type) && !(type is NullType)) {
-				var decl = get_temp_variable (target_type, true, node, false);
-				emit_temp_var (decl);
-				ccode.add_assignment (get_variable_cexpression (decl.name), get_cvalue_ (copy_value (result, node)));
-				result.cvalue = get_variable_cexpression (decl.name);
+				result = (GLibValue) copy_value (result, node);
+				// drop this assignment when target values are guaranteed to be effect-free
+				if (!(target_type is ArrayType && ((ArrayType) target_type).fixed_length)) {
+					var decl = get_temp_variable (target_type, true, node, false);
+					emit_temp_var (decl);
+					ccode.add_assignment (get_variable_cexpression (decl.name), get_cvalue_ (result));
+					result.cvalue = get_variable_cexpression (decl.name);
+				}
 			}
 		}
 
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 3169591..1f8fec7 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -75,6 +75,7 @@ TESTS = \
 	objects/bug597155.vala \
 	objects/bug597161.vala \
 	objects/bug613486.vala \
+	objects/bug613840.vala \
 	objects/bug620706.vala \
 	objects/bug624594.vala \
 	objects/bug628639.vala \
diff --git a/tests/objects/bug613840.vala b/tests/objects/bug613840.vala
new file mode 100644
index 0000000..baf7fe5
--- /dev/null
+++ b/tests/objects/bug613840.vala
@@ -0,0 +1,5 @@
+void main () {
+	Object a[1] = {new Object()};
+	Object b[1] = a;
+	assert (a[0] == b[0]);
+}