Move Winfer-union to MiniPhase

Author: Alex1005a

compiler/src/dotty/tools/dotc/Compiler.scala

@@ -34,6 +34,7 @@ class Compiler {
     List(new Parser) ::             // Compiler frontend: scanner, parser
     List(new TyperPhase) ::         // Compiler frontend: namer, typer
     List(CheckUnused.PostTyper(), CheckShadowing()) :: // Check for unused, shadowed elements
+    List(new WInferUnion) ::        // Winfer-union
     List(new YCheckPositions) ::    // YCheck positions
     List(new sbt.ExtractDependencies) :: // Sends information on classes' dependencies to sbt via callbacks
     List(new semanticdb.ExtractSemanticDB.ExtractSemanticInfo) :: // Extract info into .semanticdb files

compiler/src/dotty/tools/dotc/transform/PostTyper.scala

@@ -534,14 +534,6 @@ class PostTyper extends MacroTransform with InfoTransformer { thisPhase =>
           if (fn.symbol != defn.ChildAnnot.primaryConstructor)
             // Make an exception for ChildAnnot, which should really have AnyKind bounds
             Checking.checkBounds(args, fn.tpe.widen.asInstanceOf[PolyType])
-          if ctx.settings.Whas.inferUnion then
-            val inferredOrTypes = args.find: tpt =>
-              tpt.isInstanceOf[InferredTypeTree] && tpt.tpe.stripTypeVar.isInstanceOf[OrType]
-            inferredOrTypes.foreach: tpt =>
-              report.warning(
-                em"""|A type argument was inferred to be union type ${tpt.tpe.stripTypeVar}
-                     |This may indicate a programming error.
-                     |""", tpt.srcPos)
           fn match {
             case sel: Select =>
               val args1 = transform(args)

compiler/src/dotty/tools/dotc/transform/WInferUnion.scala

@@ -0,0 +1,32 @@
+package dotty.tools.dotc.transform
+
+import dotty.tools.dotc.ast.tpd
+import dotty.tools.dotc.ast.tpd.InferredTypeTree
+import dotty.tools.dotc.core.Contexts.{Context, ctx}
+import dotty.tools.dotc.core.Decorators.em
+import dotty.tools.dotc.core.Types.OrType
+import dotty.tools.dotc.report
+import dotty.tools.dotc.transform.MegaPhase.MiniPhase
+
+class WInferUnion extends MiniPhase {
+
+  override def phaseName: String = WInferUnion.name
+
+  override def description: String = WInferUnion.description
+
+  override def isEnabled(using Context): Boolean = ctx.settings.Whas.inferUnion
+
+  override def transformTypeApply(tree: tpd.TypeApply)(using Context): tpd.Tree =
+    val inferredOrTypes = tree.args.find: tpt =>
+      tpt.isInstanceOf[InferredTypeTree] && tpt.tpe.stripTypeVar.isInstanceOf[OrType]
+    inferredOrTypes.foreach: tpt =>
+      report.warning(
+        em"""|A type argument was inferred to be union type ${tpt.tpe.stripTypeVar}
+             |This may indicate a programming error.
+             |""", tpt.srcPos)
+    tree
+}
+
+object WInferUnion:
+  val name = "Winfer-union"
+  val description = "warn if type argument inferred as union type"