Rust: Implement basic type inference in QL

Author: hvitved

rust/ql/.generated.list

@@ -239,9 +239,8 @@ final class RecordExprCfgNode extends Nodes::RecordExprCfgNode {
   pragma[nomagic]
   ExprCfgNode getFieldExpr(string field) {
     exists(RecordExprField ref |
-      ref = node.getRecordExprFieldList().getAField() and
-      any(ChildMapping mapping).hasCfgChild(node, ref.getExpr(), this, result) and
-      field = ref.getFieldName()
+      ref = node.getFieldExpr(field) and
+      any(ChildMapping mapping).hasCfgChild(node, ref.getExpr(), this, result)
     )
   }
 }

rust/ql/.gitattributes

@@ -15,6 +15,14 @@ module Impl {
   private import rust
   private import PathResolution as PathResolution
 
+  pragma[nomagic]
+  Path getFunctionPath(CallExpr ce) { result = ce.getFunction().(PathExpr).getPath() }
+
+  pragma[nomagic]
+  PathResolution::ItemNode getResolvedFunction(CallExpr ce) {
+    result = PathResolution::resolvePath(getFunctionPath(ce))
+  }
+
   // the following QLdoc is generated: if you need to edit it, do it in the schema file
   /**
    * A function call expression. For example:
@@ -28,9 +36,15 @@ module Impl {
   class CallExpr extends Generated::CallExpr {
     override string toString() { result = this.getFunction().toAbbreviatedString() + "(...)" }
 
+    /** Gets the struct that this call resolves to, if any. */
+    Struct getStruct() { result = getResolvedFunction(this) }
+
+    /** Gets the variant that this call resolves to, if any. */
+    Variant getVariant() { result = getResolvedFunction(this) }
+
     pragma[nomagic]
-    private PathResolution::ItemNode getResolvedFunction(int pos) {
-      result = PathResolution::resolvePath(this.getFunction().(PathExpr).getPath()) and
+    private PathResolution::ItemNode getResolvedFunctionAndPos(int pos) {
+      result = getResolvedFunction(this) and
       exists(this.getArgList().getArg(pos))
     }
 
@@ -42,7 +56,7 @@ module Impl {
      */
     pragma[nomagic]
     TupleField getTupleField(int pos) {
-      exists(PathResolution::ItemNode i | i = this.getResolvedFunction(pos) |
+      exists(PathResolution::ItemNode i | i = this.getResolvedFunctionAndPos(pos) |
         result.isStructField(i, pos) or
         result.isVariantField(i, pos)
       )

rust/ql/lib/codeql/rust/controlflow/CfgNodes.qll

@@ -11,6 +11,9 @@ private import codeql.rust.elements.internal.generated.FieldExpr
  * be referenced directly.
  */
 module Impl {
+  private import rust
+  private import TypeInference as TypeInference
+
   // the following QLdoc is generated: if you need to edit it, do it in the schema file
   /**
    * A field access expression. For example:
@@ -19,6 +22,12 @@ module Impl {
    * ```
    */
   class FieldExpr extends Generated::FieldExpr {
+    /** Gets the record field that this access references, if any. */
+    RecordField getRecordField() { result = TypeInference::resolveRecordFieldExpr(this) }
+
+    /** Gets the tuple field that this access references, if any. */
+    TupleField getTupleField() { result = TypeInference::resolveTupleFieldExpr(this) }
+
     override string toString() {
       exists(string abbr, string name |
         abbr = this.getExpr().toAbbreviatedString() and

rust/ql/lib/codeql/rust/elements/internal/CallExprImpl.qll

@@ -11,6 +11,8 @@ private import codeql.rust.elements.internal.generated.GenericArgList
  * be referenced directly.
  */
 module Impl {
+  private import rust
+
   // the following QLdoc is generated: if you need to edit it, do it in the schema file
   /**
    * The base class for generic arguments.
@@ -22,5 +24,18 @@ module Impl {
     override string toString() { result = this.toAbbreviatedString() }
 
     override string toAbbreviatedString() { result = "<...>" }
+
+    /** Gets the `i`th type argument of this list. */
+    TypeRepr getTypeArgument(int i) {
+      result =
+        rank[i + 1](TypeRepr res, int j |
+          res = this.getGenericArg(j).(TypeArg).getTypeRepr()
+        |
+          res order by j
+        )
+    }
+
+    /** Gets a type argument of this list. */
+    TypeRepr getATypeArgument() { result = this.getTypeArgument(_) }
   }
 }

rust/ql/lib/codeql/rust/elements/internal/FieldExprImpl.qll

@@ -1,4 +1,3 @@
-// generated by codegen, remove this comment if you wish to edit this file
 /**
  * This module provides a hand-modifiable wrapper around the generated class `GenericParamList`.
  *
@@ -12,11 +11,26 @@ private import codeql.rust.elements.internal.generated.GenericParamList
  * be referenced directly.
  */
 module Impl {
+  private import rust
+
+  // the following QLdoc is generated: if you need to edit it, do it in the schema file
   /**
    * A GenericParamList. For example:
    * ```rust
    * todo!()
    * ```
    */
-  class GenericParamList extends Generated::GenericParamList { }
+  class GenericParamList extends Generated::GenericParamList {
+    override string toString() { result = this.toAbbreviatedString() }
+
+    override string toAbbreviatedString() { result = "<...>" }
+
+    /** Gets the `i`th type parameter of this list. */
+    TypeParam getTypeParam(int i) {
+      result = rank[i + 1](TypeParam res, int j | res = this.getGenericParam(j) | res order by j)
+    }
+
+    /** Gets a type parameter of this list. */
+    TypeParam getATypeParam() { result = this.getTypeParam(_) }
+  }
 }