Interpolate any type vars from comparing against SelectionProto (#16348)

Author: dwijnand

compiler/src/dotty/tools/dotc/inlines/Inliner.scala

@@ -749,9 +749,9 @@ class Inliner(val call: tpd.Tree)(using Context):
       ctx
 
     override def typedIdent(tree: untpd.Ident, pt: Type)(using Context): Tree =
-      val tree1 = inlineIfNeeded(
-          tryInlineArg(tree.asInstanceOf[tpd.Tree]) `orElse` super.typedIdent(tree, pt)
-        )
+      val locked = ctx.typerState.ownedVars
+      val tree0 = tryInlineArg(tree.asInstanceOf[tpd.Tree]) `orElse` super.typedIdent(tree, pt)
+      val tree1 = inlineIfNeeded(tree0, pt, locked)
       tree1 match
         case id: Ident if tpd.needsSelect(id.tpe) =>
           inlining.println(i"expanding $id to selection")
@@ -760,6 +760,7 @@ class Inliner(val call: tpd.Tree)(using Context):
           tree1
 
     override def typedSelect(tree: untpd.Select, pt: Type)(using Context): Tree = {
+      val locked = ctx.typerState.ownedVars
       val qual1 = typed(tree.qualifier, shallowSelectionProto(tree.name, pt, this))
       val resNoReduce = untpd.cpy.Select(tree)(qual1, tree.name).withType(tree.typeOpt)
       val reducedProjection = reducer.reduceProjection(resNoReduce)
@@ -771,7 +772,7 @@ class Inliner(val call: tpd.Tree)(using Context):
         if resNoReduce ne res then
           typed(res, pt) // redo typecheck if reduction changed something
         else if res.symbol.isInlineMethod then
-          inlineIfNeeded(res)
+          inlineIfNeeded(res, pt, locked)
         else
           ensureAccessible(res.tpe, tree.qualifier.isInstanceOf[untpd.Super], tree.srcPos)
           res
@@ -809,19 +810,21 @@ class Inliner(val call: tpd.Tree)(using Context):
         tree match
           case Quoted(Spliced(inner)) => inner
           case _ => tree
+      val locked = ctx.typerState.ownedVars
       val res = cancelQuotes(constToLiteral(betaReduce(super.typedApply(tree, pt)))) match {
         case res: Apply if res.symbol == defn.QuotedRuntime_exprSplice
                         && StagingContext.level == 0
                         && !hasInliningErrors =>
           val expanded = expandMacro(res.args.head, tree.srcPos)
           typedExpr(expanded) // Inline calls and constant fold code generated by the macro
         case res =>
-          specializeEq(inlineIfNeeded(res))
+          specializeEq(inlineIfNeeded(res, pt, locked))
       }
       res
 
     override def typedTypeApply(tree: untpd.TypeApply, pt: Type)(using Context): Tree =
-      val tree1 = inlineIfNeeded(constToLiteral(betaReduce(super.typedTypeApply(tree, pt))))
+      val locked = ctx.typerState.ownedVars
+      val tree1 = inlineIfNeeded(constToLiteral(betaReduce(super.typedTypeApply(tree, pt))), pt, locked)
       if tree1.symbol.isQuote then
         ctx.compilationUnit.needsStaging = true
       tree1
@@ -889,11 +892,11 @@ class Inliner(val call: tpd.Tree)(using Context):
     /** True if this inline typer has already issued errors */
     override def hasInliningErrors(using Context) = ctx.reporter.errorCount > initialErrorCount
 
-    private def inlineIfNeeded(tree: Tree)(using Context): Tree =
+    private def inlineIfNeeded(tree: Tree, pt: Type, locked: TypeVars)(using Context): Tree =
       val meth = tree.symbol
       if meth.isAllOf(DeferredInline) then
         errorTree(tree, em"Deferred inline ${meth.showLocated} cannot be invoked")
-      else if Inlines.needsInlining(tree) then Inlines.inlineCall(tree)
+      else if Inlines.needsInlining(tree) then Inlines.inlineCall(simplify(tree, pt, locked))
       else tree
 
     override def typedUnadapted(tree: untpd.Tree, pt: Type, locked: TypeVars)(using Context): Tree =

tests/pos/i16331/Macro.scala

@@ -0,0 +1,4 @@
+import scala.quoted._
+object Macro:
+  transparent inline def macroDef[A](): Int = ${ macroDefImpl() }
+  def macroDefImpl()(using q: Quotes): Expr[Int] = '{0}

tests/pos/i16331/Main.scala

@@ -0,0 +1,3 @@
+object Main:
+  inline def inlineDef[A](): Any = Macro.macroDef()
+  def main(args: Array[String]) = inlineDef()