Rust: Simplify

Author: hvitved

rust/ql/lib/codeql/rust/internal/TypeInference.qll

@@ -1759,14 +1759,14 @@ private module MethodCallMatchingInput implements MatchingWithEnvironmentInputSi
           path = TypePath::cons(TRefTypeParameter(), suffix)
         )
       else (
-        not apos.asArgumentPosition().isSelf() and
+        not apos.isSelf() and
         result = inferType(this.getNodeAt(apos), path)
       )
     }
 
     pragma[nomagic]
     Type getInferredType(string derefChainBorrow, AccessPosition apos, TypePath path) {
-      apos.asArgumentPosition().isSelf() and
+      apos.isSelf() and
       result = this.getInferredSelfType(derefChainBorrow, path)
       or
       result = this.getInferredNonSelfType(apos, path) and
@@ -1813,19 +1813,19 @@ private Type inferMethodCallType(AstNode n, TypePath path) {
     result = inferMethodCallType0(a, apos, n, derefChainBorrow, path0)
   |
     (
-      not apos.asArgumentPosition().isSelf()
+      not apos.isSelf()
       or
       derefChainBorrow = ";"
     ) and
     path = path0
     or
     // adjust for implicit deref
-    apos.asArgumentPosition().isSelf() and
+    apos.isSelf() and
     derefChainBorrow = ".ref;" and
     path = TypePath::cons(TRefTypeParameter(), path0)
     or
     // adjust for implicit borrow
-    apos.asArgumentPosition().isSelf() and
+    apos.isSelf() and
     derefChainBorrow = ";borrow" and
     path0.isCons(TRefTypeParameter(), path)
   )
@@ -1947,10 +1947,7 @@ private module NonMethodResolution {
     }
 
     AstNode getNodeAt(FunctionTypePosition pos) {
-      exists(ArgumentPosition apos |
-        apos = pos.asArgumentPosition() and
-        result = this.getArg(apos.asPosition())
-      )
+      result = this.getArg(pos.asPositional())
       or
       result = this and pos.isReturn()
     }
@@ -2243,7 +2240,7 @@ private module NonMethodCallMatchingInput implements MatchingInputSig {
 
     pragma[nomagic]
     Type getInferredType(AccessPosition apos, TypePath path) {
-      apos.asArgumentPosition().isSelf() and
+      apos.isSelf() and
       result = getCallExprTypeQualifier(this, path)
       or
       result = inferType(this.getNodeAt(apos), path)