[compiler][be] Less ambiguous error messages for validateMemo bailout

compiler/packages/babel-plugin-react-compiler/src/Validation/ValidatePreservedManualMemoization.ts

@@ -433,64 +433,74 @@ class Visitor extends ReactiveFunctionVisitor<VisitorState> {
      * recursively visits ReactiveValues and instructions
      */
     this.recordTemporaries(instruction, state);
-    if (instruction.value.kind === 'StartMemoize') {
+    const value = instruction.value;
+    if (value.kind === 'StartMemoize') {
       let depsFromSource: Array<ManualMemoDependency> | null = null;
-      if (instruction.value.deps != null) {
-        depsFromSource = instruction.value.deps;
+      if (value.deps != null) {
+        depsFromSource = value.deps;
       }
       CompilerError.invariant(state.manualMemoState == null, {
         reason: 'Unexpected nested StartMemoize instructions',
-        description: `Bad manual memoization ids: ${state.manualMemoState?.manualMemoId}, ${instruction.value.manualMemoId}`,
-        loc: instruction.value.loc,
+        description: `Bad manual memoization ids: ${state.manualMemoState?.manualMemoId}, ${value.manualMemoId}`,
+        loc: value.loc,
         suggestions: null,
       });
 
       state.manualMemoState = {
         loc: instruction.loc,
         decls: new Set(),
         depsFromSource,
-        manualMemoId: instruction.value.manualMemoId,
+        manualMemoId: value.manualMemoId,
       };
-    }
-    if (instruction.value.kind === 'FinishMemoize') {
-      CompilerError.invariant(
-        state.manualMemoState != null &&
-          state.manualMemoState.manualMemoId === instruction.value.manualMemoId,
-        {
-          reason: 'Unexpected mismatch between StartMemoize and FinishMemoize',
-          description: `Encountered StartMemoize id=${state.manualMemoState?.manualMemoId} followed by FinishMemoize id=${instruction.value.manualMemoId}`,
-          loc: instruction.value.loc,
-          suggestions: null,
-        },
-      );
-      state.manualMemoState = null;
-    }
 
-    const isDep = instruction.value.kind === 'StartMemoize';
-    const isDecl =
-      instruction.value.kind === 'FinishMemoize' && !instruction.value.pruned;
-    if (isDep || isDecl) {
-      for (const value of eachInstructionValueOperand(
-        instruction.value as InstructionValue,
+      for (const {identifier, loc} of eachInstructionValueOperand(
+        value as InstructionValue,
       )) {
         if (
-          (isDep &&
-            value.identifier.scope != null &&
-            !this.scopes.has(value.identifier.scope.id) &&
-            !this.prunedScopes.has(value.identifier.scope.id)) ||
-          (isDecl && isUnmemoized(value.identifier, this.scopes))
+          identifier.scope != null &&
+          !this.scopes.has(identifier.scope.id) &&
+          !this.prunedScopes.has(identifier.scope.id)
         ) {
           state.errors.push({
             reason:
-              'React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This value may be mutated later, which could cause the value to change unexpectedly',
+              'React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This dependency may be mutated later, which could cause the value to change unexpectedly',
             description: null,
             severity: ErrorSeverity.CannotPreserveMemoization,
-            loc: typeof instruction.loc !== 'symbol' ? instruction.loc : null,
+            loc,
             suggestions: null,
           });
         }
       }
     }
+    if (value.kind === 'FinishMemoize') {
+      CompilerError.invariant(
+        state.manualMemoState != null &&
+          state.manualMemoState.manualMemoId === value.manualMemoId,
+        {
+          reason: 'Unexpected mismatch between StartMemoize and FinishMemoize',
+          description: `Encountered StartMemoize id=${state.manualMemoState?.manualMemoId} followed by FinishMemoize id=${value.manualMemoId}`,
+          loc: value.loc,
+          suggestions: null,
+        },
+      );
+      state.manualMemoState = null;
+      if (!value.pruned) {
+        for (const {identifier, loc} of eachInstructionValueOperand(
+          value as InstructionValue,
+        )) {
+          if (isUnmemoized(identifier, this.scopes)) {
+            state.errors.push({
+              reason:
+                'React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This value was memoized in source but not in compilation output.',
+              description: null,
+              severity: ErrorSeverity.CannotPreserveMemoization,
+              loc,
+              suggestions: null,
+            });
+          }
+        }
+      }
+    }
   }
 }
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.todo-repro-unmemoized-callback-captured-in-context-variable.expect.md

@@ -53,7 +53,7 @@ export const FIXTURE_ENTRYPOINT = {
    9 |   const a = useHook();
   10 |   // Because b is also part of that same mutable range, it can't be memoized either
 > 11 |   const b = useMemo(() => ({}), []);
-     |                     ^^^^^^^^^^ CannotPreserveMemoization: React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This value may be mutated later, which could cause the value to change unexpectedly (11:11)
+     |             ^^^^^^^^^^^^^^^^^^^^^^^ CannotPreserveMemoization: React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This value was memoized in source but not in compilation output. (11:11)
   12 |
   13 |   // Conditional assignment without a subsequent mutation normally doesn't create a mutable
   14 |   // range, but in this case we're reassigning a context variable

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.todo-useCallback-accesses-ref-mutated-later-via-function-preserve-memoization.expect.md

@@ -45,7 +45,7 @@ export const FIXTURE_ENTRYPOINT = {
 > 10 |     ref.current.inner = event.target.value;
      | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 > 11 |   });
-     | ^^^^ CannotPreserveMemoization: React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This value may be mutated later, which could cause the value to change unexpectedly (7:11)
+     | ^^^^ CannotPreserveMemoization: React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This value was memoized in source but not in compilation output. (7:11)
   12 |
   13 |   // The ref is modified later, extending its range and preventing memoization of onChange
   14 |   const reset = () => {

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.todo-useCallback-set-ref-nested-property-ref-modified-later-preserve-memoization.expect.md

@@ -42,7 +42,7 @@ export const FIXTURE_ENTRYPOINT = {
 > 10 |     ref.current.inner = event.target.value;
      | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 > 11 |   });
-     | ^^^^ CannotPreserveMemoization: React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This value may be mutated later, which could cause the value to change unexpectedly (7:11)
+     | ^^^^ CannotPreserveMemoization: React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This value was memoized in source but not in compilation output. (7:11)
   12 |
   13 |   // The ref is modified later, extending its range and preventing memoization of onChange
   14 |   ref.current.inner = null;

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/preserve-memo-validation/error.false-positive-useMemo-infer-mutate-deps.expect.md

@@ -29,14 +29,10 @@ export const FIXTURE_ENTRYPOINT = {
 ## Error
 
 ```
-  10 |   const val = [1, 2, 3];
-  11 |
-> 12 |   return useMemo(() => {
-     |                  ^^^^^^^
-> 13 |     return identity(val);
-     | ^^^^^^^^^^^^^^^^^^^^^^^^^
+  12 |   return useMemo(() => {
+  13 |     return identity(val);
 > 14 |   }, [val]);
-     | ^^^^ CannotPreserveMemoization: React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This value may be mutated later, which could cause the value to change unexpectedly (12:14)
+     |       ^^^ CannotPreserveMemoization: React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This dependency may be mutated later, which could cause the value to change unexpectedly (14:14)
   15 | }
   16 |
   17 | export const FIXTURE_ENTRYPOINT = {

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/preserve-memo-validation/error.invalid-useCallback-captures-reassigned-context.expect.md

@@ -33,9 +33,9 @@ export const FIXTURE_ENTRYPOINT = {
   10 |
   11 |   // makeArray() is captured, but depsList contains [props]
 > 12 |   const cb = useCallback(() => [x], [x]);
-     |                          ^^^^^^^^^ CannotPreserveMemoization: React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This value may be mutated later, which could cause the value to change unexpectedly (12:12)
+     |                                      ^ CannotPreserveMemoization: React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This dependency may be mutated later, which could cause the value to change unexpectedly (12:12)
 
-CannotPreserveMemoization: React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This value may be mutated later, which could cause the value to change unexpectedly (12:12)
+CannotPreserveMemoization: React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This value was memoized in source but not in compilation output. (12:12)
   13 |
   14 |   x = makeArray();
   15 |

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/preserve-memo-validation/error.todo-useCallback-captures-invalidating-value.expect.md

@@ -31,7 +31,7 @@ export const FIXTURE_ENTRYPOINT = {
   11 |   x.push(props);
   12 |
 > 13 |   return useCallback(() => [x], [x]);
-     |                      ^^^^^^^^^ CannotPreserveMemoization: React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This value may be mutated later, which could cause the value to change unexpectedly (13:13)
+     |                      ^^^^^^^^^ CannotPreserveMemoization: React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This value was memoized in source but not in compilation output. (13:13)
   14 | }
   15 |
   16 | export const FIXTURE_ENTRYPOINT = {