Fix issue with type inference for result constructor.

`global x = result("foo");` would end up having type `string` instead
of `result<string>`.

hilti/toolchain/include/ast/builder/node-factory.h

@@ -106,6 +106,9 @@ class NodeFactory {
     auto ctorResult(Expression* expr, const Meta& meta = {}) {
         return hilti::ctor::Result::create(context(), expr, meta);
     }
+    auto ctorResult(QualifiedType* type, const Meta& meta = {}) {
+        return hilti::ctor::Result::create(context(), type, meta);
+    }
     auto ctorSet(Expressions exprs, Meta meta = {}) {
         return hilti::ctor::Set::create(context(), std::move(exprs), std::move(meta));
     }

hilti/toolchain/include/ast/ctors/result.h

@@ -6,8 +6,11 @@
 #include <utility>
 
 #include <hilti/ast/ctor.h>
+#include <hilti/ast/ctors/error.h>
 #include <hilti/ast/expression.h>
+#include <hilti/ast/expressions/ctor.h>
 #include <hilti/ast/type.h>
+#include <hilti/ast/types/auto.h>
 #include <hilti/ast/types/error.h>
 #include <hilti/ast/types/result.h>
 
@@ -36,24 +39,28 @@ class Result : public Ctor {
             return {};
     }
 
-    QualifiedType* type() const final {
-        if ( auto e = child<QualifiedType>(0) )
-            return e;
-        else
-            return child<Expression>(1)->type();
-    }
+    QualifiedType* type() const final { return child<QualifiedType>(0); }
 
     void setType(ASTContext* ctx, QualifiedType* t) { setChild(ctx, 0, t); }
 
     static auto create(ASTContext* ctx, Expression* expr, const Meta& meta = {}) {
         return ctx->make<Result>(ctx,
                                  {
-                                     nullptr,
+                                     QualifiedType::createAuto(ctx, meta),
                                      expr,
                                  },
                                  meta);
     }
 
+    static auto create(ASTContext* ctx, QualifiedType* type, const Meta& meta = {}) {
+        return ctx->make<Result>(ctx,
+                                 {
+                                     type,
+                                     expression::Ctor::create(ctx, ctor::Error::create(ctx, "<not set>", meta), meta),
+                                 },
+                                 meta);
+    }
+
 protected:
     Result(ASTContext* ctx, Nodes children, Meta meta) : Ctor(ctx, NodeTags, std::move(children), std::move(meta)) {}
 

hilti/toolchain/src/compiler/codegen/ctors.cc

@@ -168,7 +168,7 @@ struct Visitor : hilti::visitor::PreOrder {
     void operator()(ctor::Result* n) final {
         auto t = cg->compile(n->type(), codegen::TypeUsage::Storage);
 
-        if ( n->value()->type()->type()->isA<type::Null>() )
+        if ( n->type()->type()->isA<type::Void>() )
             result = fmt("::hilti::rt::Nothing{}");
         else if ( auto e = n->value() )
             result = fmt("%s(%s)", t, cg->compile(e));

hilti/toolchain/src/compiler/coercer.cc

@@ -71,7 +71,7 @@ struct VisitorCtor : visitor::PreOrder {
         }
 
         if ( auto t = dst->type()->tryAs<type::Result>(); t && t->dereferencedType()->type()->isA<type::Void>() ) {
-            result = builder->ctorResult(builder->expressionCtor(builder->ctorNull()));
+            result = builder->ctorResult(t->dereferencedType());
             return;
         }
 

tests/Baseline/spicy.statements.assert/output

@@ -2,3 +2,4 @@
 uncaught exception hilti::rt::AssertionFailure: failed expression '1 == 0' (fail.spicy:3:1-3:14)
 uncaught exception hilti::rt::AssertionFailure: my error (fail2.spicy:3:1-3:27)
 uncaught exception hilti::rt::AssertionFailure: my error (fail3.spicy:3:1-3:32)
+uncaught exception hilti::rt::AssertionFailure: foo (fail4.spicy:4:1-4:9)

tests/spicy/statements/assert.spicy

@@ -2,6 +2,7 @@
 # @TEST-EXEC-FAIL: spicyc -j fail.spicy >>output 2>&1
 # @TEST-EXEC-FAIL: spicyc -j fail2.spicy >>output 2>&1
 # @TEST-EXEC-FAIL: spicyc -j fail3.spicy >>output 2>&1
+# @TEST-EXEC-FAIL: spicyc -j fail4.spicy >>output 2>&1
 # @TEST-EXEC: btest-diff output
 
 module Foo;
@@ -28,3 +29,11 @@ module Foo;
 assert 1 == 0 : error"my error";
 
 @TEST-END-FILE
+
+@TEST-START-FILE fail4.spicy
+
+module Foo;
+global x = 0 : "foo";
+assert x;
+
+@TEST-END-FILE