Break out functionality from MethodType

and generalize MethodParam to ParamRef, and
TypeParamInfo to ParamInfo

1 files changed, 40 insertions, 0 deletions

diff --git a/compiler/src/dotty/tools/dotc/core/ParamInfo.scala b/compiler/src/dotty/tools/dotc/core/ParamInfo.scala
new file mode 100644
index 000000000..efae24916
--- /dev/null
+++ b/compiler/src/dotty/tools/dotc/core/ParamInfo.scala
@@ -0,0 +1,40 @@
+package dotty.tools.dotc.core
+
+import Names.TypeName
+import Contexts.Context
+import Types.{Type, TypeBounds}
+
+/** A common super trait of Symbol and LambdaParam.
+ *  Used to capture the attributes of type parameters which can be implemented as either.
+ */
+trait ParamInfo {
+
+  /** Is this the info of a type parameter? Will return `false` for symbols
+   *  that are not type parameters.
+   */
+  def isTypeParam(implicit ctx: Context): Boolean
+
+  /** The name of the type parameter */
+  def paramName(implicit ctx: Context): TypeName
+
+  /** The info of the type parameter */
+  def paramInfo(implicit ctx: Context): Type
+
+  /** The info of the type parameter as seen from a prefix type.
+   *  For type parameter symbols, this is the `memberInfo` as seen from `prefix`.
+   *  For type lambda parameters, it's the same as `paramBounds` as
+   *  `asSeenFrom` has already been applied to the whole type lambda.
+   */
+  def paramInfoAsSeenFrom(pre: Type)(implicit ctx: Context): Type
+
+  /** The parameter bounds, or the completer if the type parameter
+   *  is an as-yet uncompleted symbol.
+   */
+  def paramInfoOrCompleter(implicit ctx: Context): Type
+
+  /** The variance of the type parameter */
+  def paramVariance(implicit ctx: Context): Int
+
+  /** A type that refers to the parameter */
+  def paramRef(implicit ctx: Context): Type
+}
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