[vala/staging] vala: Keep formal_target_type when transforming method-call/object-creation

[Rico Tzschichholz <ricotz src gnome org>]

commit f4bad5fc9b05672d304472f149b416e2d0f6da82
Author: Rico Tzschichholz <ricotz ubuntu com>
Date:   Tue Nov 19 09:11:39 2019 +0100

    vala: Keep formal_target_type when transforming method-call/object-creation
    
    Fixes https://gitlab.gnome.org/GNOME/vala/issues/835

 tests/Makefile.am                               |  1 +
 tests/generics/inference-argument-may-fail.vala | 20 ++++++++++++++++++++
 vala/valamethodcall.vala                        |  2 ++
 vala/valaobjectcreationexpression.vala          |  3 +++
 4 files changed, 26 insertions(+)
---
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 01161db0a..9d2e5cc6d 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -508,6 +508,7 @@ TESTS = \
        asynchronous/yield.vala \
        generics/arrays-not-supported.test \
        generics/constructor-chain-up.vala \
+       generics/inference-argument-may-fail.vala \
        generics/inference-static-function.vala \
        generics/parameter-sizeof-initializer.vala \
        generics/member-dup-destroy.vala \
diff --git a/tests/generics/inference-argument-may-fail.vala b/tests/generics/inference-argument-may-fail.vala
new file mode 100644
index 000000000..b99b97153
--- /dev/null
+++ b/tests/generics/inference-argument-may-fail.vala
@@ -0,0 +1,20 @@
+class Foo<G> {
+       public Foo () throws Error {
+       }
+}
+
+Foo<string>? foo () throws Error {
+       return null;
+}
+
+G bar<G> (Foo<G>? foo) {
+       return null;
+}
+
+void main () {
+       try {
+               bar (foo ());
+               bar (new Foo<string> ());
+       } catch {
+       }
+}
diff --git a/vala/valamethodcall.vala b/vala/valamethodcall.vala
index 9aaa0dd04..1c6e2b404 100644
--- a/vala/valamethodcall.vala
+++ b/vala/valamethodcall.vala
@@ -646,6 +646,7 @@ public class Vala.MethodCall : Expression {
 
                value_type.check (context);
 
+               // FIXME code duplication in ObjectCreationExpression.check
                if (tree_can_fail) {
                        if (parent_node is LocalVariable || parent_node is ExpressionStatement) {
                                // simple statements, no side effects after method call
@@ -662,6 +663,7 @@ public class Vala.MethodCall : Expression {
                                insert_statement (context.analyzer.insert_block, decl);
 
                                var temp_access = SemanticAnalyzer.create_temp_access (local, target_type);
+                               temp_access.formal_target_type = formal_target_type;
 
                                // don't set initializer earlier as this changes parent_node and 
parent_statement
                                local.initializer = this;
diff --git a/vala/valaobjectcreationexpression.vala b/vala/valaobjectcreationexpression.vala
index caf9414a6..575d50b37 100644
--- a/vala/valaobjectcreationexpression.vala
+++ b/vala/valaobjectcreationexpression.vala
@@ -499,6 +499,7 @@ public class Vala.ObjectCreationExpression : Expression {
                        context.analyzer.visit_member_initializer (init, type_reference);
                }
 
+               // FIXME code duplication in MethodCall.check
                if (tree_can_fail) {
                        if (parent_node is LocalVariable || parent_node is ExpressionStatement) {
                                // simple statements, no side effects after method call
@@ -515,6 +516,8 @@ public class Vala.ObjectCreationExpression : Expression {
                                insert_statement (context.analyzer.insert_block, decl);
 
                                var temp_access = SemanticAnalyzer.create_temp_access (local, target_type);
+                               temp_access.formal_target_type = formal_target_type;
+
                                // don't set initializer earlier as this changes parent_node and 
parent_statement
                                local.initializer = this;
                                decl.check (context);