support casts in initializers

rework of #710, reuses the existing type construction

Co-authored-by: ryuukk <ryuukk.dev@gmail.com>

dsymbol/src/dsymbol/conversion/first.d

@@ -1133,9 +1133,10 @@ private:
 		auto lookup = l ? l : TypeLookupsAllocator.instance.make!TypeLookup(TypeLookupKind.varOrFunType);
 
 		lookup.breadcrumbs.insert(TYPEOF_SYMBOL_NAME);
-		scope (exit)
-			lookup.breadcrumbs.insert(TYPEOF_END_SYMBOL_NAME);
 		scope visitor = new InitializerVisitor(lookup, appendForeach, this);
+		scope (exit)
+			if (!visitor.isCast)
+				lookup.breadcrumbs.insert(TYPEOF_END_SYMBOL_NAME);
 
 		if (l is null)
 			lookups.insert(lookup);
@@ -1586,6 +1587,25 @@ class InitializerVisitor : ASTVisitor
 		on = false;
 	}
 
+	override void visit(const CastExpression expression)
+	{
+		if (expression.type)
+		{
+			if (lookup.breadcrumbs.empty || lookup.breadcrumbs.back != TYPEOF_SYMBOL_NAME)
+				return;
+
+			isCast = true;
+			lookup.breadcrumbs.popBack();
+			TypeLookups none;
+			fp.addTypeToLookups(none, expression.type, lookup);
+		}
+		else
+		{
+			// we don't care about non-type casts (e.g. `cast()` or `cast(const)`) yet
+			expression.accept(this);
+		}
+	}
+
 	override void dynamicDispatch(const ExpressionNode expression)
 	{
 		on = true;
@@ -1599,6 +1619,7 @@ class InitializerVisitor : ASTVisitor
 	bool on = false;
 	const bool appendForeach;
 	FirstPass fp;
+	bool isCast;
 }
 
 class ArgumentListVisitor : ASTVisitor

tests/tc_casts/expected1.txt

@@ -0,0 +1,8 @@
+identifiers
+alignof	k
+init	k
+inside_c	v
+mangleof	k
+sizeof	k
+stringof	k
+tupleof	k

tests/tc_casts/file.d

@@ -0,0 +1,26 @@
+struct A
+{
+	struct B
+	{
+		struct C
+		{
+			int inside_c;
+		}
+		int inside_b;
+	}
+	int inside_a;
+}
+
+unittest
+{
+	auto from_cast = cast(A.B.C) nonExist;
+	from_cast.
+}
+
+unittest
+{
+	struct A {}
+
+	auto from_cast = cast(A.B.C) nonExist;
+	from_cast.
+}

tests/tc_casts/run.sh

@@ -0,0 +1,8 @@
+set -e
+set -u
+
+../../bin/dcd-client $1 file.d -c159 > actual1.txt
+diff actual1.txt expected1.txt --strip-trailing-cr
+
+../../bin/dcd-client $1 file.d -c239 > actual2.txt
+diff actual2.txt expected2.txt --strip-trailing-cr