Fix failing non-null checks (#1151)

Author: dcodeIO

src/compiler.ts

@@ -2592,9 +2592,6 @@ export class Compiler extends DiagnosticEmitter {
     var flow = this.currentFlow;
     var returnType = flow.returnType;
 
-    // Remember that this flow returns
-    flow.set(FlowFlags.RETURNS | FlowFlags.TERMINATES);
-
     var valueExpression = statement.value;
     if (valueExpression) {
       if (returnType == Type.void) {
@@ -2633,6 +2630,9 @@ export class Compiler extends DiagnosticEmitter {
     }
     flow.freeScopedLocals();
 
+    // Remember that this flow returns
+    flow.set(FlowFlags.RETURNS | FlowFlags.TERMINATES);
+
     // If the last statement anyway, make it the block's return value
     if (isLastInBody && expr != 0 && returnType != Type.void) {
       if (!stmts.length) return expr;
@@ -5711,7 +5711,7 @@ export class Compiler extends DiagnosticEmitter {
       target,
       expr, // TODO: delay release above if possible?
       this.currentType,
-      left,
+      right,
       resolver.currentThisExpression,
       resolver.currentElementExpression,
       contextualType != Type.void
@@ -5850,12 +5850,13 @@ export class Compiler extends DiagnosticEmitter {
 
     // compile the value and do the assignment
     assert(targetType != Type.void);
-    var valueExpr = this.compileExpression(valueExpression, targetType, Constraints.CONV_IMPLICIT | Constraints.WILL_RETAIN);
+    var valueExpr = this.compileExpression(valueExpression, targetType, Constraints.WILL_RETAIN);
+    var valueType = this.currentType;
     return this.makeAssignment(
       target,
-      valueExpr,
-      this.currentType,
-      expression,
+      this.convertExpression(valueExpr, valueType, targetType, false, false, valueExpression),
+      valueType,
+      valueExpression,
       thisExpression,
       elementExpression,
       contextualType != Type.void

src/flow.ts

@@ -764,35 +764,48 @@ export class Flow {
 
     this.flags = newFlags | (this.flags & FlowFlags.UNCHECKED_CONTEXT);
 
-    var leftLocalFlags = left.localFlags;
-    var numLeftLocalFlags = leftLocalFlags.length;
-    var rightLocalFlags = right.localFlags;
-    var numRightLocalFlags = rightLocalFlags.length;
-    var maxLocalFlags = max(numLeftLocalFlags, numRightLocalFlags);
-    var combinedFlags = new Array<LocalFlags>(maxLocalFlags);
-    for (let i = 0; i < maxLocalFlags; ++i) {
-      let leftFlags = i < numLeftLocalFlags ? leftLocalFlags[i] : 0;
-      let rightFlags = i < numRightLocalFlags ? rightLocalFlags[i] : 0;
-      let newFlags = leftFlags & rightFlags & (
-        LocalFlags.CONSTANT  |
-        LocalFlags.WRAPPED   |
-        LocalFlags.NONNULL   |
-        LocalFlags.INITIALIZED
-      );
-      if (leftFlags & LocalFlags.RETAINED) {
-        if (rightFlags & LocalFlags.RETAINED) {
-          newFlags |= LocalFlags.RETAINED;
-        } else {
+    var thisLocalFlags = this.localFlags;
+    if (leftFlags & FlowFlags.TERMINATES) {
+      if (!(rightFlags & FlowFlags.TERMINATES)) {
+        let rightLocalFlags = right.localFlags;
+        for (let i = 0, k = rightLocalFlags.length; i < k; ++i) {
+          thisLocalFlags[i] = rightLocalFlags[i];
+        }
+      }
+    } else if (rightFlags & FlowFlags.TERMINATES) {
+      let leftLocalFlags = left.localFlags;
+      for (let i = 0, k = leftLocalFlags.length; i < k; ++i) {
+        thisLocalFlags[i] = leftLocalFlags[i];
+      }
+    } else {
+      let leftLocalFlags = left.localFlags;
+      let numLeftLocalFlags = leftLocalFlags.length;
+      let rightLocalFlags = right.localFlags;
+      let numRightLocalFlags = rightLocalFlags.length;
+      let maxLocalFlags = max(numLeftLocalFlags, numRightLocalFlags);
+      for (let i = 0; i < maxLocalFlags; ++i) {
+        let leftFlags = i < numLeftLocalFlags ? leftLocalFlags[i] : 0;
+        let rightFlags = i < numRightLocalFlags ? rightLocalFlags[i] : 0;
+        let newFlags = leftFlags & rightFlags & (
+          LocalFlags.CONSTANT  |
+          LocalFlags.WRAPPED   |
+          LocalFlags.NONNULL   |
+          LocalFlags.INITIALIZED
+        );
+        if (leftFlags & LocalFlags.RETAINED) {
+          if (rightFlags & LocalFlags.RETAINED) {
+            newFlags |= LocalFlags.RETAINED;
+          } else {
+            newFlags |= LocalFlags.CONDITIONALLY_RETAINED;
+          }
+        } else if (rightFlags & LocalFlags.RETAINED) {
           newFlags |= LocalFlags.CONDITIONALLY_RETAINED;
+        } else {
+          newFlags |= (leftFlags | rightFlags) & LocalFlags.CONDITIONALLY_RETAINED;
         }
-      } else if (rightFlags & LocalFlags.RETAINED) {
-        newFlags |= LocalFlags.CONDITIONALLY_RETAINED;
-      } else {
-        newFlags |= (leftFlags | rightFlags) & LocalFlags.CONDITIONALLY_RETAINED;
+        thisLocalFlags[i] = newFlags;
       }
-      combinedFlags[i] = newFlags;
     }
-    this.localFlags = combinedFlags;
   }
 
   /** Tests if the specified flows have differing local states. */

src/parser.ts

@@ -1296,7 +1296,6 @@ export class Parser extends DiagnosticEmitter {
         if (!type) return null;
       } else {
         type = Node.createOmittedType(tn.range(tn.pos));
-        type = type!; // FIXME: WHY?
       }
       let initializer: Expression | null = null;
       if (tn.skip(Token.EQUALS)) {
@@ -1423,7 +1422,6 @@ export class Parser extends DiagnosticEmitter {
       returnType = Node.createOmittedType(
         tn.range(tn.pos)
       );
-      returnType = returnType!; // FIXME: WHY?
       if (!isSetter) {
         this.error(
           DiagnosticCode.Type_expected,
@@ -1532,7 +1530,6 @@ export class Parser extends DiagnosticEmitter {
       if (!returnType) return null;
     } else {
       returnType = Node.createOmittedType(tn.range(tn.pos));
-      returnType = returnType!; // FIXME: WHY?
     }
 
     if (arrowKind) {
@@ -2082,7 +2079,6 @@ export class Parser extends DiagnosticEmitter {
         if (!returnType) return null;
       } else {
         returnType = Node.createOmittedType(tn.range(tn.pos));
-        returnType = returnType!; // FIXME: WHY?
         if (!isSetter && name.kind != NodeKind.CONSTRUCTOR) {
           this.error(
             DiagnosticCode.Type_expected,
@@ -3543,7 +3539,6 @@ export class Parser extends DiagnosticEmitter {
           return null;
         }
         inner = Node.createParenthesizedExpression(inner, tn.range(startPos, tn.pos));
-        inner = inner!; // FIXME: WHY?
         return this.maybeParseCallExpression(tn, inner);
       }
       // ArrayLiteralExpression
@@ -3833,7 +3828,6 @@ export class Parser extends DiagnosticEmitter {
             null,
             tn.range(startPos, tn.pos)
           );
-          expr = expr!; // FIXME: WHY?
           expr = this.maybeParseCallExpression(tn, expr);
           break;
         }
@@ -3864,7 +3858,6 @@ export class Parser extends DiagnosticEmitter {
             next,
             tn.range(startPos, tn.pos)
           );
-          expr = expr!; // FIXME: WHY?
           expr = this.maybeParseCallExpression(tn, expr);
           break;
         }
@@ -3932,7 +3925,6 @@ export class Parser extends DiagnosticEmitter {
               <IdentifierExpression>next,
               tn.range(startPos, tn.pos)
             );
-            expr = expr!; // FIXME: WHY?
           } else {
             let next = this.parseExpression(tn, nextPrecedence + 1);
             if (!next) return null;