wip4

Author: hvitved

shared/typeinference/codeql/typeinference/internal/TypeInference.qll

@@ -2421,9 +2421,9 @@ module Make1<LocationSig Location, InputSig1<Location> Input1> {
       private import Input3
 
       private predicate closureStep(AstNode pattern, TypePath path1, Closure c, TypePath path2) {
-        exists(int index, Parameter p |
+        exists(Parameter p |
           pattern = p.getPattern() and
-          p = c.getParameter(index) and
+          p = c.getParameter(_) and
           path1.isEmpty() and
           path2 = getClosureParameterTypePath(p)
         )
@@ -3157,26 +3157,24 @@ module Make1<LocationSig Location, InputSig1<Location> Input1> {
         CachedStage::ref() and
         result = inferTypeCertain(n, path)
         or
+        result = inferType0(n, path) and
         // Don't propagate type information into a node which conflicts with certain
         // type information.
-        result = inferType0(n, path) and
         forall(TypePath prefix |
           Certain::hasInferredCertainType(n, prefix) and
           prefix.isPrefixOf(path)
         |
           not Certain::certainTypeConflict(n, prefix, path, result)
           or
-          // propagate closure parameter pseudo types even when there is certain information,
-          // but prevent those types from escaping from the closure
-          exists(Parameter p |
-            result.(ClosureParameterPseudoType).getParameter() = p and
-            not p = n.(Closure).getParameter(_)
-          )
-        )
+          // propagate closure parameter pseudo types even when there is certain information
+          result instanceof ClosureParameterPseudoType
+        ) and
+        // prevent closure parameter pseudo types from escaping from the closure
+        not result.(ClosureParameterPseudoType).getParameter() = n.(Closure).getParameter(_)
         or
         // If `n` has an explicitly unknown type at `prefix` and at the same time a certain
         // type at `prefix.suffix`, then extend the unknown type information to any path
-        // extending `prefix.suffix` where there is no certain type information
+        // extending `prefix.suffix` where there is not also certain type information
         exists(TypePath prefix, TypePath suffix, Type certain, TypeParameter tp |
           inferType0(n, prefix) instanceof UnknownType and
           certain = inferTypeCertain(n, prefix.appendInverse(suffix)) and
@@ -3189,6 +3187,10 @@ module Make1<LocationSig Location, InputSig1<Location> Input1> {
         infersTypeAt(n, path, result.getATypeParameter())
       }
 
+      /**
+       * Holds if `n` has type information at the type path `prefix.tp`. This entails
+       * that the type at `prefix` must be the type that declares `tp`.
+       */
       pragma[nomagic]
       private predicate infersTypeAt(AstNode n, TypePath prefix, TypeParameter tp) {
         exists(TypePath path |
@@ -3201,6 +3203,7 @@ module Make1<LocationSig Location, InputSig1<Location> Input1> {
       /**
        * Gets the inferred root type of `n`, if any.
        */
+      pragma[nomagic]
       Type inferType(AstNode n) { result = inferType(n, TypePath::nil()) }
 
       /**
@@ -3238,7 +3241,7 @@ module Make1<LocationSig Location, InputSig1<Location> Input1> {
         }
 
         /**
-         * Checks that `Input3::inferType` is an alias for `inferType`.
+         * Checks that `Input3::inferTypeForDefaults` is an alias for `inferType`.
          */
         query predicate inferTypeMismatch(AstNode n, TypePath path, Type t) {
           inferType(n, path) = t and
@@ -3251,6 +3254,10 @@ module Make1<LocationSig Location, InputSig1<Location> Input1> {
 
       /** Provides various debugging predicates. */
       module Debug {
+        /**
+         * Holds if `n` has reached the type path limit. This is usually indicative
+         * of an unintended type inference explosion.
+         */
         pragma[nomagic]
         predicate atLimit(AstNode n) {
           exists(TypePath path0 |