fix(neverAccessedVariables): False positive on contract constants

These are not supported, so we have to remove the logic introduced here
after #22 is implemented.

src/detectors/builtin/neverAccessedVariables.ts

@@ -179,10 +179,13 @@ export class NeverAccessedVariables extends Detector {
   }
 
   collectDefinedConstants(cu: CompilationUnit): Set<[ConstantName, ASTRef]> {
-    return Array.from(cu.ast.getConstants()).reduce((acc, constant) => {
-      acc.add([constant.name, constant.ref]);
-      return acc;
-    }, new Set<[ConstantName, ASTRef]>());
+    return Array.from(cu.ast.getConstants({ includeContract: false })).reduce(
+      (acc, constant) => {
+        acc.add([constant.name, constant.ref]);
+        return acc;
+      },
+      new Set<[ConstantName, ASTRef]>(),
+    );
   }
 
   /**

src/internals/ir.ts

@@ -25,6 +25,7 @@ export class TactASTStore {
   /**
    * Constructs a TactASTStore with mappings to all major AST components.
    * @param stdlibIds Identifiers of AST elements defined in stdlib.
+   * @param contractConstants Identifiers of constants defined within contracts (XXX: remove after #22 is fixed)
    * @param programEntries Identifiers of AST elements defined on the top-level.
    * @param functions Functions and methods including user-defined and special methods.
    * @param constants Constants defined across the compilation unit.
@@ -37,6 +38,7 @@ export class TactASTStore {
    */
   constructor(
     private stdlibIds = new Set<number>(),
+    private contractConstants = new Set<number>(),
     private programEntries: Set<number>,
     private functions: Map<number, ASTFunction | ASTReceive | ASTInitFunction>,
     private constants: Map<number, ASTConstant>,
@@ -110,11 +112,27 @@ export class TactASTStore {
    * and contract constants.
    * @param params Additional parameters:
    * - includeStdlib: If true, includes constants defined in stdlib.
+   * - includeContract: If true, includes contstants defined within a contract.
+   *   XXX: This won't compile since Tact 1.4.1, remove it after #22 is merged
    */
   getConstants(
-    params: Partial<{ includeStdlib: boolean }> = {},
+    params: Partial<{ includeStdlib: boolean; includeContract: boolean }> = {},
   ): IterableIterator<ASTConstant> {
-    return this.getItems(this.constants, params);
+    const { includeContract = false } = params;
+    const constants = this.getItems(this.constants, params);
+    function* filterIterator(
+      iterator: IterableIterator<ASTConstant>,
+      condition: (item: ASTConstant) => boolean,
+    ): IterableIterator<ASTConstant> {
+      for (const item of iterator) {
+        if (condition(item)) {
+          yield item;
+        }
+      }
+    }
+    return includeContract
+      ? constants
+      : filterIterator(constants, (c) => !this.contractConstants.has(c.id));
   }
 
   getContracts(): IterableIterator<ASTContract> {

src/internals/tactIRBuilder.ts

@@ -103,6 +103,7 @@ function hasSubdirs(filePath: string, subdirs: string[]): boolean {
 export class ASTMapper {
   private programEntries = new Set<number>();
   private stdlibIds = new Set<number>();
+  private contractConstants = new Set<number>();
   private functions = new Map<
     number,
     ASTFunction | ASTReceive | ASTInitFunction
@@ -149,6 +150,7 @@ export class ASTMapper {
   public getASTStore(): TactASTStore {
     return new TactASTStore(
       this.stdlibIds,
+      this.contractConstants,
       this.programEntries,
       this.functions,
       this.constants,
@@ -194,6 +196,7 @@ export class ASTMapper {
           break;
         case "def_constant":
           this.constants.set(decl.id, decl);
+          this.contractConstants.add(decl.id);
           break;
         default:
           throw new Error(`Unsupported contract declaration: ${decl}`);

test/contracts/never-accessed-4.cfg.json

@@ -0,0 +1,25 @@
+{
+  "projectName": "never-accessed-4",
+  "functions": [],
+  "contracts": [
+    {
+      "name": "ConstantFieldTest",
+      "methods": [
+        {
+          "name": "ConstantFieldTest.test",
+          "cfg": {
+            "nodes": [
+              {
+                "id": 1566,
+                "stmtID": 21139,
+                "srcEdges": [],
+                "dstEdges": []
+              }
+            ],
+            "edges": []
+          }
+        }
+      ]
+    }
+  ]
+}

test/contracts/never-accessed-4.expected.out

@@ -0,0 +1 @@
+

test/contracts/never-accessed-4.tact

@@ -0,0 +1,13 @@
+// NOTE: This example won't compile after updating Tact to 1.4.1
+contract ConstantFieldTest {
+    const val: Int = ton("0.01");
+    fun test() {
+        send(SendParameters{
+            to: sender(),
+            bounce: true,
+            value: self.val,
+            mode: SendRemainingValue + SendIgnoreErrors
+        });
+    }
+}
+

test/contracts/readonly-1.cfg.json

@@ -6,101 +6,101 @@
       "cfg": {
         "nodes": [
           {
-            "id": 1566,
-            "stmtID": 21125,
+            "id": 1717,
+            "stmtID": 23340,
             "srcEdges": [],
             "dstEdges": [
-              1568
+              1719
             ]
           },
           {
-            "id": 1567,
-            "stmtID": 21128,
+            "id": 1718,
+            "stmtID": 23343,
             "srcEdges": [
-              1568
+              1719
             ],
             "dstEdges": [
-              1570
+              1721
             ]
           },
           {
-            "id": 1569,
-            "stmtID": 21131,
+            "id": 1720,
+            "stmtID": 23346,
             "srcEdges": [
-              1570
+              1721
             ],
             "dstEdges": [
-              1572
+              1723
             ]
           },
           {
-            "id": 1571,
-            "stmtID": 21138,
+            "id": 1722,
+            "stmtID": 23353,
             "srcEdges": [
-              1572
+              1723
             ],
             "dstEdges": [
-              1574,
-              1578
+              1725,
+              1729
             ]
           },
           {
-            "id": 1573,
-            "stmtID": 21137,
+            "id": 1724,
+            "stmtID": 23352,
             "srcEdges": [
-              1574
+              1725
             ],
             "dstEdges": [
-              1576
+              1727
             ]
           },
           {
-            "id": 1575,
-            "stmtID": 21140,
+            "id": 1726,
+            "stmtID": 23355,
             "srcEdges": [
-              1576
+              1727
             ],
             "dstEdges": []
           },
           {
-            "id": 1577,
-            "stmtID": 21140,
+            "id": 1728,
+            "stmtID": 23355,
             "srcEdges": [
-              1578
+              1729
             ],
             "dstEdges": []
           }
         ],
         "edges": [
           {
-            "id": 1568,
-            "src": 1566,
-            "dst": 1567
+            "id": 1719,
+            "src": 1717,
+            "dst": 1718
           },
           {
-            "id": 1570,
-            "src": 1567,
-            "dst": 1569
+            "id": 1721,
+            "src": 1718,
+            "dst": 1720
           },
           {
-            "id": 1572,
-            "src": 1569,
-            "dst": 1571
+            "id": 1723,
+            "src": 1720,
+            "dst": 1722
           },
           {
-            "id": 1574,
-            "src": 1571,
-            "dst": 1573
+            "id": 1725,
+            "src": 1722,
+            "dst": 1724
           },
           {
-            "id": 1576,
-            "src": 1573,
-            "dst": 1575
+            "id": 1727,
+            "src": 1724,
+            "dst": 1726
           },
           {
-            "id": 1578,
-            "src": 1571,
-            "dst": 1577
+            "id": 1729,
+            "src": 1722,
+            "dst": 1728
           }
         ]
       }

test/contracts/readonly-2.cfg.json

@@ -6,42 +6,42 @@
       "cfg": {
         "nodes": [
           {
-            "id": 1728,
-            "stmtID": 23209,
+            "id": 1879,
+            "stmtID": 25424,
             "srcEdges": [],
             "dstEdges": [
-              1730
+              1881
             ]
           },
           {
-            "id": 1729,
-            "stmtID": 23212,
+            "id": 1880,
+            "stmtID": 25427,
             "srcEdges": [
-              1730
+              1881
             ],
             "dstEdges": [
-              1732
+              1883
             ]
           },
           {
-            "id": 1731,
-            "stmtID": 23214,
+            "id": 1882,
+            "stmtID": 25429,
             "srcEdges": [
-              1732
+              1883
             ],
             "dstEdges": []
           }
         ],
         "edges": [
           {
-            "id": 1730,
-            "src": 1728,
-            "dst": 1729
+            "id": 1881,
+            "src": 1879,
+            "dst": 1880
           },
           {
-            "id": 1732,
-            "src": 1729,
-            "dst": 1731
+            "id": 1883,
+            "src": 1880,
+            "dst": 1882
           }
         ]
       }