diff --git a/packages/react-reconciler/src/ReactStrictModeWarnings.js b/packages/react-reconciler/src/ReactStrictModeWarnings.js
index 29af663d90ec..a61185d8bf5f 100644
--- a/packages/react-reconciler/src/ReactStrictModeWarnings.js
+++ b/packages/react-reconciler/src/ReactStrictModeWarnings.js
@@ -324,6 +324,11 @@ if (__DEV__) {
   ReactStrictModeWarnings.flushLegacyContextWarning = () => {
     ((pendingLegacyContextWarning: any): FiberToFiberComponentsMap).forEach(
       (fiberArray: FiberArray, strictRoot) => {
+        if (fiberArray.length === 0) {
+          return;
+        }
+        const firstFiber = fiberArray[0];
+
         const uniqueNames = new Set();
         fiberArray.forEach(fiber => {
           uniqueNames.add(getComponentName(fiber.type) || 'Component');
@@ -331,9 +336,7 @@ if (__DEV__) {
         });
 
         const sortedNames = setToSortedString(uniqueNames);
-        const strictRootComponentStack = getStackByFiberInDevAndProd(
-          strictRoot,
-        );
+        const firstComponentStack = getStackByFiberInDevAndProd(firstFiber);
 
         console.error(
           'Legacy context API has been detected within a strict-mode tree.' +
@@ -343,7 +346,7 @@ if (__DEV__) {
             '\n\nLearn more about this warning here: https://fb.me/react-legacy-context' +
             '%s',
           sortedNames,
-          strictRootComponentStack,
+          firstComponentStack,
         );
       },
     );
diff --git a/packages/react-reconciler/src/__tests__/ReactIncremental-test.internal.js b/packages/react-reconciler/src/__tests__/ReactIncremental-test.internal.js
index e39b055f79c5..a5e1a0ace5d2 100644
--- a/packages/react-reconciler/src/__tests__/ReactIncremental-test.internal.js
+++ b/packages/react-reconciler/src/__tests__/ReactIncremental-test.internal.js
@@ -1917,7 +1917,6 @@ describe('ReactIncremental', () => {
         'The old API will be supported in all 16.x releases, but applications ' +
         'using it should migrate to the new version.\n\n' +
         'Please update the following components: Intl, ShowBoth, ShowLocale',
-      {withoutStack: true},
     );
 
     ReactNoop.render(
@@ -1974,7 +1973,6 @@ describe('ReactIncremental', () => {
         'The old API will be supported in all 16.x releases, but applications ' +
         'using it should migrate to the new version.\n\n' +
         'Please update the following components: Router, ShowRoute',
-      {withoutStack: true},
     );
   });
 
@@ -2000,14 +1998,11 @@ describe('ReactIncremental', () => {
     }
 
     ReactNoop.render(<Recurse />);
-    expect(() =>
-      expect(Scheduler).toFlushWithoutYielding(),
-    ).toErrorDev(
+    expect(() => expect(Scheduler).toFlushWithoutYielding()).toErrorDev(
       'Legacy context API has been detected within a strict-mode tree.\n\n' +
         'The old API will be supported in all 16.x releases, but applications ' +
         'using it should migrate to the new version.\n\n' +
         'Please update the following components: Recurse',
-      {withoutStack: true},
     );
     expect(ops).toEqual([
       'Recurse {}',
@@ -2041,20 +2036,17 @@ describe('ReactIncremental', () => {
     };
 
     ReactNoop.render(<Recurse />);
-    expect(() => expect(Scheduler).toFlushWithoutYielding()).toErrorDev(
-      [
-        'Warning: The <Recurse /> component appears to be a function component that returns a class instance. ' +
-          'Change Recurse to a class that extends React.Component instead. ' +
-          "If you can't use a class try assigning the prototype on the function as a workaround. " +
-          '`Recurse.prototype = React.Component.prototype`. ' +
-          "Don't use an arrow function since it cannot be called with `new` by React.",
-        'Legacy context API has been detected within a strict-mode tree.\n\n' +
-          'The old API will be supported in all 16.x releases, but applications ' +
-          'using it should migrate to the new version.\n\n' +
-          'Please update the following components: Recurse',
-      ],
-      {withoutStack: 1},
-    );
+    expect(() => expect(Scheduler).toFlushWithoutYielding()).toErrorDev([
+      'Warning: The <Recurse /> component appears to be a function component that returns a class instance. ' +
+        'Change Recurse to a class that extends React.Component instead. ' +
+        "If you can't use a class try assigning the prototype on the function as a workaround. " +
+        '`Recurse.prototype = React.Component.prototype`. ' +
+        "Don't use an arrow function since it cannot be called with `new` by React.",
+      'Legacy context API has been detected within a strict-mode tree.\n\n' +
+        'The old API will be supported in all 16.x releases, but applications ' +
+        'using it should migrate to the new version.\n\n' +
+        'Please update the following components: Recurse',
+    ]);
     expect(ops).toEqual([
       'Recurse {}',
       'Recurse {"n":2}',
@@ -2120,7 +2112,6 @@ describe('ReactIncremental', () => {
         'The old API will be supported in all 16.x releases, but applications ' +
         'using it should migrate to the new version.\n\n' +
         'Please update the following components: Intl, ShowLocale',
-      {withoutStack: true},
     );
   });
 
@@ -2196,14 +2187,11 @@ describe('ReactIncremental', () => {
         </IndirectionFn>
       </Intl>,
     );
-    expect(() =>
-      expect(Scheduler).toFlushWithoutYielding(),
-    ).toErrorDev(
+    expect(() => expect(Scheduler).toFlushWithoutYielding()).toErrorDev(
       'Legacy context API has been detected within a strict-mode tree.\n\n' +
         'The old API will be supported in all 16.x releases, but applications ' +
         'using it should migrate to the new version.\n\n' +
         'Please update the following components: Intl, ShowLocaleClass, ShowLocaleFn',
-      {withoutStack: true},
     );
     expect(ops).toEqual([
       'Intl:read {}',
@@ -2292,14 +2280,11 @@ describe('ReactIncremental', () => {
         </IndirectionFn>
       </Stateful>,
     );
-    expect(() =>
-      expect(Scheduler).toFlushWithoutYielding(),
-    ).toErrorDev(
+    expect(() => expect(Scheduler).toFlushWithoutYielding()).toErrorDev(
       'Legacy context API has been detected within a strict-mode tree.\n\n' +
         'The old API will be supported in all 16.x releases, but applications ' +
         'using it should migrate to the new version.\n\n' +
         'Please update the following components: Intl, ShowLocaleClass, ShowLocaleFn',
-      {withoutStack: true},
     );
     expect(ops).toEqual([
       'Intl:read {}',
@@ -2365,14 +2350,11 @@ describe('ReactIncremental', () => {
 
     // Init
     ReactNoop.render(<Root />);
-    expect(() =>
-      expect(Scheduler).toFlushWithoutYielding(),
-    ).toErrorDev(
+    expect(() => expect(Scheduler).toFlushWithoutYielding()).toErrorDev(
       'Legacy context API has been detected within a strict-mode tree.\n\n' +
         'The old API will be supported in all 16.x releases, but applications ' +
         'using it should migrate to the new version.\n\n' +
         'Please update the following components: Child',
-      {withoutStack: true},
     );
 
     // Trigger an update in the middle of the tree
@@ -2419,14 +2401,11 @@ describe('ReactIncremental', () => {
 
     // Init
     ReactNoop.render(<Root />);
-    expect(() =>
-      expect(Scheduler).toFlushWithoutYielding(),
-    ).toErrorDev(
+    expect(() => expect(Scheduler).toFlushWithoutYielding()).toErrorDev(
       'Legacy context API has been detected within a strict-mode tree.\n\n' +
         'The old API will be supported in all 16.x releases, but applications ' +
         'using it should migrate to the new version.\n\n' +
         'Please update the following components: ContextProvider',
-      {withoutStack: true},
     );
 
     // Trigger an update in the middle of the tree
@@ -2479,7 +2458,7 @@ describe('ReactIncremental', () => {
           'using it should migrate to the new version.\n\n' +
           'Please update the following components: MyComponent',
       ],
-      {withoutStack: true},
+      {withoutStack: 1},
     );
 
     expect(ops).toEqual([
@@ -2622,14 +2601,11 @@ describe('ReactIncremental', () => {
       </TopContextProvider>,
     );
 
-    expect(() =>
-      expect(Scheduler).toFlushWithoutYielding(),
-    ).toErrorDev(
+    expect(() => expect(Scheduler).toFlushWithoutYielding()).toErrorDev(
       'Legacy context API has been detected within a strict-mode tree.\n\n' +
         'The old API will be supported in all 16.x releases, but applications ' +
         'using it should migrate to the new version.\n\n' +
         'Please update the following components: Child, TopContextProvider',
-      {withoutStack: true},
     );
     expect(rendered).toEqual(['count:0']);
     instance.updateCount();
@@ -2688,14 +2664,11 @@ describe('ReactIncremental', () => {
       </TopContextProvider>,
     );
 
-    expect(() =>
-      expect(Scheduler).toFlushWithoutYielding(),
-    ).toErrorDev(
+    expect(() => expect(Scheduler).toFlushWithoutYielding()).toErrorDev(
       'Legacy context API has been detected within a strict-mode tree.\n\n' +
         'The old API will be supported in all 16.x releases, but applications ' +
         'using it should migrate to the new version.\n\n' +
         'Please update the following components: Child, MiddleContextProvider, TopContextProvider',
-      {withoutStack: true},
     );
     expect(rendered).toEqual(['count:0']);
     instance.updateCount();
@@ -2763,14 +2736,11 @@ describe('ReactIncremental', () => {
       </TopContextProvider>,
     );
 
-    expect(() =>
-      expect(Scheduler).toFlushWithoutYielding(),
-    ).toErrorDev(
+    expect(() => expect(Scheduler).toFlushWithoutYielding()).toErrorDev(
       'Legacy context API has been detected within a strict-mode tree.\n\n' +
         'The old API will be supported in all 16.x releases, but applications ' +
         'using it should migrate to the new version.\n\n' +
         'Please update the following components: Child, MiddleContextProvider, TopContextProvider',
-      {withoutStack: true},
     );
     expect(rendered).toEqual(['count:0']);
     instance.updateCount();
@@ -2848,14 +2818,11 @@ describe('ReactIncremental', () => {
       </TopContextProvider>,
     );
 
-    expect(() =>
-      expect(Scheduler).toFlushWithoutYielding(),
-    ).toErrorDev(
+    expect(() => expect(Scheduler).toFlushWithoutYielding()).toErrorDev(
       'Legacy context API has been detected within a strict-mode tree.\n\n' +
         'The old API will be supported in all 16.x releases, but applications ' +
         'using it should migrate to the new version.\n\n' +
         'Please update the following components: Child, MiddleContextProvider, TopContextProvider',
-      {withoutStack: true},
     );
     expect(rendered).toEqual(['count:0, name:brian']);
     topInstance.updateCount();
@@ -2956,10 +2923,9 @@ describe('ReactIncremental', () => {
       ReactNoop.render(<Boundary />);
       expect(() => {
         expect(Scheduler).toFlushWithoutYielding();
-      }).toErrorDev(
-        ['Legacy context API has been detected within a strict-mode tree'],
-        {withoutStack: true},
-      );
+      }).toErrorDev([
+        'Legacy context API has been detected within a strict-mode tree',
+      ]);
     }
 
     // First, verify that this code path normally receives Fibers as keys,
diff --git a/packages/react-reconciler/src/__tests__/ReactIncrementalErrorHandling-test.internal.js b/packages/react-reconciler/src/__tests__/ReactIncrementalErrorHandling-test.internal.js
index 519c2d3f3a85..bcb74b6ea07f 100644
--- a/packages/react-reconciler/src/__tests__/ReactIncrementalErrorHandling-test.internal.js
+++ b/packages/react-reconciler/src/__tests__/ReactIncrementalErrorHandling-test.internal.js
@@ -1148,14 +1148,11 @@ describe('ReactIncrementalErrorHandling', () => {
         <Connector />
       </Provider>,
     );
-    expect(() =>
-      expect(Scheduler).toFlushWithoutYielding(),
-    ).toErrorDev(
+    expect(() => expect(Scheduler).toFlushWithoutYielding()).toErrorDev(
       'Legacy context API has been detected within a strict-mode tree.\n\n' +
         'The old API will be supported in all 16.x releases, but ' +
         'applications using it should migrate to the new version.\n\n' +
         'Please update the following components: Connector, Provider',
-      {withoutStack: true},
     );
 
     // If the context stack does not unwind, span will get 'abcde'
@@ -1649,19 +1646,16 @@ describe('ReactIncrementalErrorHandling', () => {
     ReactNoop.render(<Provider />);
     expect(() => {
       expect(Scheduler).toFlushAndThrow('Oops!');
-    }).toErrorDev(
-      [
-        'Warning: The <Provider /> component appears to be a function component that returns a class instance. ' +
-          'Change Provider to a class that extends React.Component instead. ' +
-          "If you can't use a class try assigning the prototype on the function as a workaround. " +
-          '`Provider.prototype = React.Component.prototype`. ' +
-          "Don't use an arrow function since it cannot be called with `new` by React.",
-        'Legacy context API has been detected within a strict-mode tree.\n\n' +
-          'The old API will be supported in all 16.x releases, but ' +
-          'applications using it should migrate to the new version.\n\n' +
-          'Please update the following components: Provider',
-      ],
-      {withoutStack: 1},
-    );
+    }).toErrorDev([
+      'Warning: The <Provider /> component appears to be a function component that returns a class instance. ' +
+        'Change Provider to a class that extends React.Component instead. ' +
+        "If you can't use a class try assigning the prototype on the function as a workaround. " +
+        '`Provider.prototype = React.Component.prototype`. ' +
+        "Don't use an arrow function since it cannot be called with `new` by React.",
+      'Legacy context API has been detected within a strict-mode tree.\n\n' +
+        'The old API will be supported in all 16.x releases, but ' +
+        'applications using it should migrate to the new version.\n\n' +
+        'Please update the following components: Provider',
+    ]);
   });
 });
diff --git a/packages/react-reconciler/src/__tests__/ReactIncrementalPerf-test.internal.js b/packages/react-reconciler/src/__tests__/ReactIncrementalPerf-test.internal.js
index a88cd8e3a89f..08c569c23950 100644
--- a/packages/react-reconciler/src/__tests__/ReactIncrementalPerf-test.internal.js
+++ b/packages/react-reconciler/src/__tests__/ReactIncrementalPerf-test.internal.js
@@ -371,7 +371,7 @@ describe('ReactDebugFiberPerf', () => {
         'Using UNSAFE_componentWillUpdate in strict mode is not recommended',
         'Legacy context API has been detected within a strict-mode tree',
       ],
-      {withoutStack: true},
+      {withoutStack: 3},
     );
     ReactNoop.render(<AllLifecycles />);
     addComment('Update');
diff --git a/packages/react-reconciler/src/__tests__/ReactNewContext-test.internal.js b/packages/react-reconciler/src/__tests__/ReactNewContext-test.internal.js
index 03c5ad4eec66..34d854f78cdd 100644
--- a/packages/react-reconciler/src/__tests__/ReactNewContext-test.internal.js
+++ b/packages/react-reconciler/src/__tests__/ReactNewContext-test.internal.js
@@ -1198,7 +1198,6 @@ describe('ReactNewContext', () => {
           'The old API will be supported in all 16.x releases, but applications ' +
           'using it should migrate to the new version.\n\n' +
           'Please update the following components: LegacyProvider',
-        {withoutStack: true},
       );
       expect(ReactNoop.getChildren()).toEqual([span('Child')]);
 
diff --git a/packages/react/src/__tests__/ReactStrictMode-test.js b/packages/react/src/__tests__/ReactStrictMode-test.js
index 15b2ce719c76..3acdab4ac3b5 100644
--- a/packages/react/src/__tests__/ReactStrictMode-test.js
+++ b/packages/react/src/__tests__/ReactStrictMode-test.js
@@ -878,6 +878,7 @@ describe('context legacy', () => {
         'FunctionalLegacyContextConsumer, LegacyContextConsumer, LegacyContextProvider' +
         '\n\nLearn more about this warning here: ' +
         'https://fb.me/react-legacy-context' +
+        '\n    in LegacyContextProvider (at **)' +
         '\n    in StrictMode (at **)' +
         '\n    in div (at **)' +
         '\n    in Root (at **)',