Don't unpickle the body of inline defs twice

The body of an inline def appears both in its rhs and in an annotation,
this commit makes sure we share the same tree for both instead of
unpickling it twice.

Author: smarter

compiler/src/dotty/tools/dotc/core/tasty/TreeUnpickler.scala

@@ -729,8 +729,15 @@ class TreeUnpickler(reader: TastyReader,
       val localCtx = localContext(sym)
 
       def readRhs(implicit ctx: Context) =
-        if (nothingButMods(end)) EmptyTree
-        else readLater(end, rdr => ctx => rdr.readTerm()(ctx.retractMode(Mode.InSuperCall)))
+        if (nothingButMods(end))
+          EmptyTree
+        else if (sym.isInlinedMethod)
+          // The body of an inline method is stored in an annotation, so no need to unpickle it again
+          new Trees.Lazy[Tree] {
+            def complete(implicit ctx: Context) = typer.Inliner.bodyToInline(sym)
+          }
+        else
+          readLater(end, rdr => ctx => rdr.readTerm()(ctx.retractMode(Mode.InSuperCall)))
 
       def ValDef(tpt: Tree) =
         ta.assignType(untpd.ValDef(sym.name.asTermName, tpt, readRhs(localCtx)), sym)