build: enable noImplicitReturns compiler option (#16672)

Turns on the `noImplicitReturns` compiler option and fixes any errors that show up as a result.

Fixes #16669.

(cherry picked from commit cf70c43)

Author: crisbeto

src/bazel-tsconfig-build.json

@@ -12,6 +12,7 @@
     "noUnusedParameters": true,
     "noUnusedLocals": true,
     "strictNullChecks": true,
+    "noImplicitReturns": true,
     "strictFunctionTypes": true,
     "noFallthroughCasesInSwitch": true,
     "noImplicitAny": true,

src/cdk/overlay/position/flexible-connected-position-strategy.ts

@@ -574,6 +574,7 @@ export class FlexibleConnectedPositionStrategy implements PositionStrategy {
 
       return verticalFit && horizontalFit;
     }
+    return false;
   }
 
   /**

src/cdk/schematics/tsconfig.json

@@ -8,6 +8,7 @@
     "outDir": "../../../dist/packages/cdk/schematics",
     "noEmitOnError": false,
     "strictNullChecks": true,
+    "noImplicitReturns": true,
     "skipDefaultLibCheck": true,
     "skipLibCheck": true,
     "sourceMap": true,

src/cdk/tree/nested-node.ts

@@ -126,10 +126,8 @@ export class CdkNestedTreeNode<T> extends CdkTreeNode<T> implements AfterContent
   private _getNodeOutlet() {
     const outlets = this.nodeOutlet;
 
-    if (outlets) {
-      // Note that since we use `descendants: true` on the query, we have to ensure
-      // that we don't pick up the outlet of a child node by accident.
-      return outlets.find(outlet => !outlet._node || outlet._node === this);
-    }
+    // Note that since we use `descendants: true` on the query, we have to ensure
+    // that we don't pick up the outlet of a child node by accident.
+    return outlets && outlets.find(outlet => !outlet._node || outlet._node === this);
   }
 }

src/dev-app/tsconfig-aot.json

@@ -9,6 +9,7 @@
     "noUnusedParameters": true,
     "noUnusedLocals": true,
     "strictNullChecks": true,
+    "noImplicitReturns": true,
     "strictFunctionTypes": true,
     "noImplicitAny": true,
     "noImplicitThis": true,

src/dev-app/tsconfig-build.json

@@ -10,6 +10,7 @@
     "noUnusedParameters": true,
     "noUnusedLocals": true,
     "strictNullChecks": true,
+    "noImplicitReturns": true,
     "strictFunctionTypes": true,
     "noImplicitThis": true,
     "lib": ["es6", "es2015", "dom"],

src/material-examples/tsconfig-build.json

@@ -10,6 +10,7 @@
     "noUnusedParameters": true,
     "noUnusedLocals": true,
     "strictNullChecks": true,
+    "noImplicitReturns": true,
     "strictFunctionTypes": true,
     "noImplicitAny": true,
     "noImplicitThis": true,

src/material-moment-adapter/tsconfig-build.json

@@ -10,6 +10,7 @@
     "noUnusedParameters": true,
     "noUnusedLocals": true,
     "strictNullChecks": true,
+    "noImplicitReturns": true,
     "strictFunctionTypes": true,
     "noImplicitAny": true,
     "noImplicitThis": true,

src/material/progress-bar/progress-bar.ts

@@ -188,6 +188,7 @@ export class MatProgressBar extends _MatProgressBarMixinBase implements CanColor
       const scale = this.bufferValue / 100;
       return {transform: `scaleX(${scale})`};
     }
+    return undefined;
   }
 
   ngAfterViewInit() {

src/material/schematics/tsconfig.json

@@ -6,6 +6,7 @@
     "outDir": "../../../dist/packages/material/schematics",
     "noEmitOnError": false,
     "strictNullChecks": true,
+    "noImplicitReturns": true,
     "skipDefaultLibCheck": true,
     "noUnusedLocals": true,
     "noUnusedParameters": true,