Unified: Type inference first version

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

@@ -2579,7 +2579,7 @@ module Make1<LocationSig Location, InputSig1<Location> Input1> {
             or
             exists(Parameter p, Variable v |
               implicitParameterDecl(p, v) and
-              result = p.getType().getTypeAt(path) and
+              tm = p.getType() and
               n = v.getAnAccess()
             )
           )
@@ -2606,6 +2606,7 @@ module Make1<LocationSig Location, InputSig1<Location> Input1> {
             or
             exists(VariableDeclaration decl |
               decl.preservesInitializerType() and
+              not exists(decl.getType()) and
               n1 = decl.getInitializer() and
               n2 = decl.getPattern()
             )

unified/ql/consistency-queries/TypeInferenceConsistency.ql

@@ -0,0 +1,8 @@
+/**
+ * @name Type inference inconsistencies
+ * @description Lists the type inference inconsistencies in the database.  This query is intended for internal use.
+ * @kind table
+ * @id unified/diagnostics/type-inference-consistency
+ */
+
+import codeql.unified.internal.typeinference.TypeInferenceConsistency

unified/ql/lib/codeql/Definitions.qll

@@ -10,7 +10,7 @@ private import codeql.unified.internal.NameBinding
  */
 cached
 predicate definitionOf(Identifier reference, NameBinding definition, string kind) {
-  definition = getStaticBindingTarget(reference) and
+  definition = getStaticBindingTargetFromIdentifier(reference) and
   not reference instanceof NameBinding and
   kind = "name"
 }

unified/ql/lib/codeql/unified/internal/AnalysisQuality.qll

@@ -13,7 +13,7 @@ module StaticNameResolutionStats implements EntityStatsSig {
    */
   private predicate resolvesToValue(Identifier name) {
     exists(AstNode decl |
-      decl = getStaticBindingTarget(name).getDeclaration() and
+      decl = getStaticBindingTargetFromIdentifier(name).getDeclaration() and
       not decl instanceof ClassLikeDeclaration and
       not decl instanceof TypeAliasDeclaration and
       not decl instanceof TypeParameter and
@@ -49,7 +49,7 @@ module StaticNameResolutionStats implements EntityStatsSig {
     }
 
     NameBindingNode getTarget() {
-      result.asIdentifier() = getStaticBindingTarget(this)
+      result.asIdentifier() = getStaticBindingTargetFromIdentifier(this)
       or
       result.isModuleScopeNode(_) and
       result.(NamespaceNode).ref().isIdentifier(this)

unified/ql/lib/codeql/unified/internal/ExprPositions.qll

@@ -1,8 +1,9 @@
 private import unified
 private import NameBinding as NameBinding
+private import ExprPositionsPlugin
 
 /**
- * Holds if `expr` appears in the context of a type annotation.
+ * Holds if `expr` appears in a context where it must refer to a type.
  */
 predicate isInTypeContext(Expr expr) {
   expr = any(TypeCastExpr n).getType()
@@ -27,8 +28,22 @@ predicate isInTypeContext(Expr expr) {
   or
   expr = any(AssociatedTypeDeclaration n).getBound()
   or
+  expr = any(ClassLikeDeclaration c).getExtensionTarget()
+  or
+  expr = any(GenericTypeExpr gte).getATypeArgument()
+  or
   expr.getParent() instanceof TypeConstraint
   or
+  exists(Identifier id | id = NameBinding::getStaticBindingTargetFromRef(expr) |
+    id = any(ClassLikeDeclaration c).getNameNode()
+    or
+    id = any(TypeAliasDeclaration t).getNameNode()
+    or
+    id = any(TypeParameter t).getNameNode()
+  )
+  or
+  any(ExprPositionsPlugin p).isInTypeContext(expr)
+  or
   isInTypeContext(expr.getEnclosingExpr())
 }
 

unified/ql/lib/codeql/unified/internal/ExprPositionsPlugin.qll

@@ -0,0 +1,10 @@
+private import unified
+private import codeql.util.Unit
+
+private module Plugins {
+  private import ExprPositionsPluginSwift
+}
+
+class ExprPositionsPlugin extends Unit {
+  predicate isInTypeContext(Expr e) { none() }
+}

unified/ql/lib/codeql/unified/internal/ExprPositionsPluginSwift.qll

@@ -0,0 +1,6 @@
+private import unified
+private import ExprPositionsPlugin
+
+private class ExprPositionsPluginSwift extends ExprPositionsPlugin {
+  override predicate isInTypeContext(Expr e) { e = any(GenericTypeExpr g).getBase() }
+}

unified/ql/lib/codeql/unified/internal/FacadeAst.qll

@@ -150,8 +150,7 @@ module Unified {
     /** Gets a direct base class of this class. */
     ClassLikeDeclaration getABaseClass() {
       result.getNameNode() =
-        NameBinding::getStaticBindingTarget(NameBinding::getIdentifierFromRef(this.getABaseType()
-                .getType()))
+        NameBinding::getStaticBindingTargetFromRef(this.getABaseType().getType())
     }
   }
 
@@ -217,6 +216,12 @@ module Unified {
     }
   }
 
+  /** A tuple expression. */
+  class TupleExpr extends G::TupleExpr {
+    /** Gets the number of elements in this tuple expression. */
+    int getNumberOfElements() { result = count(this.getAnElement()) }
+  }
+
   class TypeAliasDeclaration extends G::TypeAliasDeclaration {
     /** Gets the name of this type alias. */
     string getName() { result = this.getNameNode().getValue() }
@@ -274,4 +279,10 @@ module Unified {
       result = count(Argument arg | arg = this.getAnArgument() and arg.isPositional())
     }
   }
+
+  /** A function expression. */
+  class FunctionExpr extends G::FunctionExpr {
+    /** Gets the number of parameters of this function. */
+    int getNumberOfParameters() { result = count(this.getAParameter()) }
+  }
 }

unified/ql/lib/codeql/unified/internal/StaticNameBinding.qll

@@ -717,14 +717,25 @@ module Public {
   }
 }
 
-/** Gets the declaration being accessed by `access`, as determined by static name binding. */
-NameBinding getStaticBindingTarget(Identifier access) {
+/** Gets the declaration being accessed by identifier `i`, as determined by static name binding. */
+NameBinding getStaticBindingTargetFromIdentifier(Identifier i) {
   // For unqualified accesses, use the shadowing-aware lookup
-  result = access.(UnqualifiedMemberAccess).getTarget()
+  result = i.(UnqualifiedMemberAccess).getTarget()
   or
   // For others, just follow the name binding graph
-  not access instanceof UnqualifiedMemberAccess and
-  trackNameBinding(result).asIdentifier() = access
+  not i instanceof UnqualifiedMemberAccess and
+  trackNameBinding(result).asIdentifier() = i
+}
+
+/**
+ * Gets the declaration being accessed by `access`, as determined by static name binding.
+ *
+ * Unlike `getStaticBindingTargetFromIdentifier`, this works with any AST node that contains
+ * a reference to an identifier, for example `x.foo` and `foo<Int>` resolve to whatever the
+ * identifiers `foo` resolve to.
+ */
+NameBinding getStaticBindingTargetFromRef(AstNode access) {
+  result = getStaticBindingTargetFromIdentifier(getIdentifierFromRef(access))
 }
 
 /**

unified/ql/lib/codeql/unified/internal/dataflow/CallGraph.qll

@@ -1,16 +1,7 @@
 private import unified
 private import AllDataFlow
-private import codeql.unified.internal.NameBinding as N
-
-private Callable getCallableFromNameBinding(NameBinding binding) {
-  binding = result.(FunctionDeclaration).getNameNode()
-}
+private import codeql.unified.internal.typeinference.TypeInference as T
 
 DataFlowCallable viableCallable(DataFlowCall c) {
-  exists(CallExpr call, Callable callable, NameBinding target |
-    c.asExplicitCall() = call and
-    target = N::getStaticBindingTarget(N::getIdentifierFromRef(call.getCallee())) and
-    callable = getCallableFromNameBinding(target) and
-    result.asSourceCallable() = callable
-  )
+  result.asSourceCallable() = T::resolveCallTarget(c.asExplicitCall())
 }