From: Simon Werbeck <simon.werbeck@gmail.com>
Date: Wed, 26 Nov 2014 13:08:41 +0000 (+0100)
Subject: Allow 'static' lambdas before chainup
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f5a4f20e12b3cecc87ffb3e4e4a42e1cfb192e88;p=thirdparty%2Fvala.git

Allow 'static' lambdas before chainup

If a lambda expression does not use its instance parameter, it is safe
to use before a chainup expression. To make this work, usage of 'this'
has to be tracked and the code generator needs to make use of this
information.

https://bugzilla.gnome.org/show_bug.cgi?id=567269
---

diff --git a/codegen/valaccodebasemodule.vala b/codegen/valaccodebasemodule.vala
index d93db9c19..4fd0105fa 100644
--- a/codegen/valaccodebasemodule.vala
+++ b/codegen/valaccodebasemodule.vala
@@ -5634,7 +5634,7 @@ public abstract class Vala.CCodeBaseModule : CodeGenerator {
 				set_delegate_target_destroy_notify (lambda, new CCodeConstant ("NULL"));
 			}
 			set_delegate_target (lambda, delegate_target);
-		} else if (get_this_type () != null) {
+		} else if (lambda.method.binding == MemberBinding.INSTANCE && get_this_type () != null) {
 			CCodeExpression delegate_target = get_result_cexpression ("self");
 			delegate_target = convert_to_generic_pointer (delegate_target, get_this_type ());
 			if (expr_owned || delegate_type.is_called_once) {
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 718601fc3..ab30ae345 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -62,6 +62,7 @@ TESTS = \
 	chainup/class-object.vala \
 	chainup/class-this.vala \
 	chainup/class-this-foo.vala \
+	chainup/class-with-lambda.vala \
 	chainup/method-lambda-base.vala \
 	chainup/no-chainup.vala \
 	chainup/struct-base.vala \
diff --git a/tests/chainup/class-with-lambda.vala b/tests/chainup/class-with-lambda.vala
new file mode 100644
index 000000000..6f5c1d0be
--- /dev/null
+++ b/tests/chainup/class-with-lambda.vala
@@ -0,0 +1,22 @@
+public class Foo : Object {
+	public Foo.lambda_after () {
+		this ();
+		SourceFunc f = () => this != null;
+		assert (f ());
+	}
+
+	public Foo.lambda_before () {
+		SourceFunc f = () => {
+			SourceFunc g = () => true;
+			return g ();
+		};
+		this ();
+		assert (f ());
+	}
+}
+
+void main () {
+	Foo foo;
+	foo = new Foo.lambda_after ();
+	foo = new Foo.lambda_before ();
+}
diff --git a/vala/valalambdaexpression.vala b/vala/valalambdaexpression.vala
index 6d0264e2c..737b79d74 100644
--- a/vala/valalambdaexpression.vala
+++ b/vala/valalambdaexpression.vala
@@ -239,6 +239,17 @@ public class Vala.LambdaExpression : Expression {
 
 		method.check (context);
 
+		if (in_creation_method && method.this_parameter != null) {
+			if (!method.this_parameter.used) {
+				method.scope.remove ("this");
+				method.this_parameter = null;
+				method.binding = MemberBinding.STATIC;
+			} else if (m != null && m.this_parameter != null) {
+				// track usage inside nested lambda expressions
+				m.this_parameter.used |= method.this_parameter.used;
+			}
+		}
+
 		value_type = new MethodType (method);
 		value_type.value_owned = target_type.value_owned;
 
@@ -256,7 +267,7 @@ public class Vala.LambdaExpression : Expression {
 		if (method.closure) {
 			method.get_captured_variables ((Collection<LocalVariable>) collection);
 		}
-		if (in_creation_method) {
+		if (in_creation_method && method.this_parameter != null && method.this_parameter.used) {
 			Symbol sym = (Block) parent_statement.parent_node;
 			do {
 				sym = sym.parent_symbol;
diff --git a/vala/valamemberaccess.vala b/vala/valamemberaccess.vala
index 85f8bbb63..3bc9eb13b 100644
--- a/vala/valamemberaccess.vala
+++ b/vala/valamemberaccess.vala
@@ -281,6 +281,7 @@ public class Vala.MemberAccess : Expression {
 						inner.value_type = this_parameter.variable_type.copy ();
 						inner.value_type.value_owned = false;
 						inner.symbol_reference = this_parameter;
+						inner.symbol_reference.used = true;
 
 						symbol_reference = inner.value_type.get_member (member_name);
 					}
@@ -508,6 +509,17 @@ public class Vala.MemberAccess : Expression {
 				local.captured = true;
 				block.captured = true;
 			}
+
+			// track usage of instance parameter for flow analysis.
+			// When accessing generic type information, instance access
+			// is needed to copy/destroy generic values.
+			var generic_type = local.variable_type as GenericType;
+			if (generic_type != null && generic_type.type_parameter.parent_symbol is TypeSymbol) {
+				var m = context.analyzer.current_method_or_property_accessor as Method;
+				if (m != null && m.binding == MemberBinding.INSTANCE) {
+					m.this_parameter.used = true;
+				}
+			}
 		} else if (member is Parameter) {
 			var param = (Parameter) member;
 			var m = param.parent_symbol as Method;
@@ -548,6 +560,17 @@ public class Vala.MemberAccess : Expression {
 					acc.body.captured = true;
 				}
 			}
+
+			// track usage of instance parameter for flow analysis.
+			// When accessing generic type information, instance access
+			// is needed to copy/destroy generic values.
+			var generic_type = param.variable_type as GenericType;
+			if (generic_type != null && generic_type.type_parameter.parent_symbol is TypeSymbol) {
+				m = context.analyzer.current_method_or_property_accessor as Method;
+				if (m != null && m.binding == MemberBinding.INSTANCE) {
+					m.this_parameter.used = true;
+				}
+			}
 		} else if (member is Field) {
 			var f = (Field) member;
 			access = f.access;
@@ -796,6 +819,7 @@ public class Vala.MemberAccess : Expression {
 				inner.value_type = this_parameter.variable_type.copy ();
 				inner.value_type.value_owned = false;
 				inner.symbol_reference = this_parameter;
+				inner.symbol_reference.used = true;
 			} else {
 				check_lvalue_access ();
 			}