Lower UDRE to TypeValue if it references a value generic

include/swift/AST/Expr.h

@@ -1385,8 +1385,47 @@ public:
     return E->getKind() == ExprKind::Type;
   }
 };
-  
-  
+
+class TypeValueExpr : public Expr {
+  TypeLoc paramTypeLoc;
+
+public:
+  /// Create a \c TypeValueExpr from an underlying parameter \c TypeRepr.
+  TypeValueExpr(TypeRepr *paramRepr) :
+      Expr(ExprKind::TypeValue, /*implicit*/ false), paramTypeLoc(paramRepr) {}
+
+  /// Create a \c TypeValueExpr for a given \c TypeDecl at the specified
+  /// location.
+  ///
+  /// The given location must be valid. If it is not, you must use
+  /// \c TypeExpr::createImplicitForDecl instead.
+  static TypeValueExpr *createForDecl(DeclNameLoc Loc, TypeDecl *D,
+                                      DeclContext *DC);
+
+  TypeRepr *getParamTypeRepr() const {
+    return paramTypeLoc.getTypeRepr();
+  }
+
+  /// Retrieves the corresponding parameter type of the value referenced by this
+  /// expression.
+  ArchetypeType *getParamType() const {
+    return paramTypeLoc.getType()->castTo<ArchetypeType>();
+  }
+
+  /// Sets the corresponding parameter type of the value referenced by this
+  /// expression.
+  void setParamType(Type paramType) {
+    paramTypeLoc.setType(paramType);
+  }
+
+  SourceRange getSourceRange() const {
+    return paramTypeLoc.getSourceRange();
+  }
+
+  static bool classof(const Expr *E) {
+    return E->getKind() == ExprKind::TypeValue;
+  }
+};
 
 /// A reference to another initializer from within a constructor body,
 /// either to a delegating initializer or to a super.init invocation.
@@ -3531,18 +3570,6 @@ public:
   }
 };
 
-/// The implicit conversion from a variable generic metatype to its underlying
-/// value type.
-class TypeValueExpr : public ImplicitConversionExpr {
-public:
-  TypeValueExpr(Expr *subExpr, Type ty)
-    : ImplicitConversionExpr(ExprKind::TypeValue, subExpr, ty) {}
-  
-  static bool classof(const Expr *E) {
-    return E->getKind() == ExprKind::TypeValue;
-  }
-};
-
 /// Extracts the isolation of a dynamically isolated function value.
 class ExtractFunctionIsolationExpr : public Expr {
   /// The function value expression from which to extract the

include/swift/AST/ExprNodes.def

@@ -191,8 +191,7 @@ ABSTRACT_EXPR(ImplicitConversion, Expr)
   EXPR(LinearFunctionExtractOriginal, ImplicitConversionExpr)
   EXPR(LinearToDifferentiableFunction, ImplicitConversionExpr)
   EXPR(ActorIsolationErasure, ImplicitConversionExpr)
-  EXPR(TypeValue, ImplicitConversionExpr)
-  EXPR_RANGE(ImplicitConversion, Load, TypeValue)
+  EXPR_RANGE(ImplicitConversion, Load, ActorIsolationErasure)
 ABSTRACT_EXPR(ExplicitCast, Expr)
   ABSTRACT_EXPR(CheckedCast, ExplicitCastExpr)
     EXPR(ForcedCheckedCast, CheckedCastExpr)
@@ -218,8 +217,9 @@ UNCHECKED_EXPR(OneWay, Expr)
 EXPR(Tap, Expr)
 UNCHECKED_EXPR(TypeJoin, Expr)
 EXPR(MacroExpansion, Expr)
+EXPR(TypeValue, Expr)
 // Don't forget to update the LAST_EXPR below when adding a new Expr here.
-LAST_EXPR(MacroExpansion)
+LAST_EXPR(TypeValue)
 
 #undef EXPR_RANGE
 #undef LITERAL_EXPR