[vala/wip/issue/991] vala: Forbid cast of floating-type literal to pointer

[Rico Tzschichholz <ricotz src gnome org>]

commit a82ad5fd26a0da0b1a95c7470341e068523b5951
Author: Rico Tzschichholz <ricotz ubuntu com>
Date:   Sat May 9 13:35:07 2020 +0200

    vala: Forbid cast of floating-type literal to pointer
    
    Fixes https://gitlab.gnome.org/GNOME/vala/issues/991

 tests/Makefile.am                        |  2 ++
 tests/basic-types/floats-boxed-cast.vala |  7 +++++++
 tests/generics/floating-type-cast.vala   |  9 +++++++++
 vala/valacastexpression.vala             | 21 +++++++++++++++++++++
 4 files changed, 39 insertions(+)
---
diff --git a/tests/Makefile.am b/tests/Makefile.am
index d5038fd9d..2bbd07efe 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -24,6 +24,7 @@ TESTS = \
        basic-types/integers.vala \
        basic-types/escape-chars.vala \
        basic-types/floats.vala \
+       basic-types/floats-boxed-cast.vala \
        basic-types/boolean.vala \
        basic-types/custom-types.vala \
        basic-types/default-gtype.vala \
@@ -569,6 +570,7 @@ TESTS = \
        asynchronous/yield.vala \
        generics/arrays-not-supported.test \
        generics/constructor-chain-up.vala \
+       generics/floating-type-cast.vala \
        generics/inference-argument-may-fail.vala \
        generics/inference-static-function.vala \
        generics/parameter-sizeof-initializer.vala \
diff --git a/tests/basic-types/floats-boxed-cast.vala b/tests/basic-types/floats-boxed-cast.vala
new file mode 100644
index 000000000..86e9f52cf
--- /dev/null
+++ b/tests/basic-types/floats-boxed-cast.vala
@@ -0,0 +1,7 @@
+void main () {
+       var f = (float?) 23.0f;
+       assert (f == 23.0f);
+
+       var d = (double?) 42.0;
+       assert (d == 42.0);
+}
diff --git a/tests/generics/floating-type-cast.vala b/tests/generics/floating-type-cast.vala
new file mode 100644
index 000000000..9475a4219
--- /dev/null
+++ b/tests/generics/floating-type-cast.vala
@@ -0,0 +1,9 @@
+void foo<G,T> (G g, T t) {
+       assert ((float?) g == 23.0f);
+       assert ((double?) t == 42.0);
+}
+
+void main () {
+       foo ((float?) 23.0f, (double?) 42.0);
+       foo<float?,double?> ((float?) 23.0f, (double?) 42.0);
+}
diff --git a/vala/valacastexpression.vala b/vala/valacastexpression.vala
index d51b4e205..45d5d1e83 100644
--- a/vala/valacastexpression.vala
+++ b/vala/valacastexpression.vala
@@ -172,6 +172,27 @@ public class Vala.CastExpression : Expression {
                        }
                }
 
+               // Implicit transformation of stack-allocated floating-type to boxed-type
+               if (!(is_silent_cast || is_non_null_cast) && inner.value_type is FloatingType && 
!inner.value_type.nullable) {
+                       if (type_reference is PointerType || (type_reference is ValueType && 
type_reference.nullable)) {
+                               var local = new LocalVariable (type_reference, get_temp_name (), null, 
inner.source_reference);
+                               var decl = new DeclarationStatement (local, source_reference);
+
+                               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 = inner;
+                               decl.check (context);
+
+                               context.analyzer.replaced_nodes.add (this);
+                               parent_node.replace_expression (this, temp_access);
+                               return temp_access.check (context);
+                       }
+               }
+
                value_type = type_reference;
                value_type.value_owned = inner.value_type.value_owned;
                value_type.floating_reference = inner.value_type.floating_reference;