Move safe transforms to a separate AST visitor pass

src/index.lsc

@@ -14,15 +14,16 @@ import { getShadowingIdentifiers, checkFalsePositiveReference } from "./variable
 import { ensureConstructor, bindMethodsInConstructor, bindMethods } from "./classes";
 import * as matching from "./match";
 import * as comprehension from "./comprehension";
-import { transformExistentialExpression, maybeTransformSafe } from "./safe";
+import { transformExistentialExpression } from "./safe";
 import { replaceWithInlinedOperator } from "./inlinedOperators";
 import { transformForInArrayStatement, transformForInObjectStatement, lintForInArrayStatement, lintForInObjectStatement } from "./for";
 import { resetHelpers } from "./helpers";
 import { markIdentifier } from "./stdlib";
 import { locatePluginOpts, getParserOpts, parseConfigurationDirectives } from './config'
 import { getFileTypeInfo, createCompilerState, initializeCompilerState, postprocess } from './compilerState'
-import { fixAst } from './fixAst'
-import { transformPlaceholders } from './placeholders'
+import { fixAst } from './passes/fixAst'
+import { transformPlaceholders } from './passes/transformPlaceholders'
+import { transformSafeExprs } from './passes/transformSafeExprs'
 import { transformPipeOperator } from './pipe'
 
 Lightscript(babel) ->
@@ -51,10 +52,11 @@ Lightscript(babel) ->
     //// AST transforms
     // Perform basic ast fixups (block bodies, etc)
     fixAst(path)
-
     // Transform placeholder expressions first.
     if compilerState.opts.placeholderArgs:
       transformPlaceholders(path)
+    // Transform safe exprs
+    transformSafeExprs(path)
 
     // Main LSC transforms
     path.traverse({
@@ -90,9 +92,6 @@ Lightscript(babel) ->
           comprehension.transformPlainObjectComprehension(path)
 
       CallExpression: {
-        enter(path): void ->
-          maybeTransformSafe(path)
-
         exit(path): void ->
           { node } = path
           if replaceWithInlinedOperator(path, node.callee, node.arguments): return
@@ -223,12 +222,6 @@ Lightscript(babel) ->
         awaitExpr = t.awaitExpression(awaitIife)~allAtLoc(getLoc(path.node))
         path.replaceWith(awaitExpr)
 
-      MemberExpression(path): void ->
-        path~maybeTransformSafe()
-
-      NewExpression(path): void ->
-        path~maybeTransformSafe()
-
       AwaitExpression(path): void ->
         if (path.get("argument").isArrayExpression() || path.node.argument.type === "ArrayComprehension") {
           const promiseDotAllCall = t.callExpression(

src/fixAst.lsc → src/passes/fixAst.lsc

@@ -1,9 +1,9 @@
 // Perform non-semantic AST transformations like ensuring function bodies
 // are blocks, etc.
-import { isNamedArrowFunction } from './functions'
-import { toBlockStatement } from './blocks'
-import { isa } from './is'
-import { ensureBlockArrowFunctionExpression } from './functions'
+import { isNamedArrowFunction } from '../functions'
+import { toBlockStatement } from '../blocks'
+import { isa } from '../is'
+import { ensureBlockArrowFunctionExpression } from '../functions'
 
 export fixAst(programPath) ->
   programPath.traverse({

src/passes/transformPlaceholders.lsc

@@ -0,0 +1,3 @@
+import { transformPlaceholders } from '../placeholders'
+
+export { transformPlaceholders }

src/passes/transformSafeExprs.lsc

@@ -0,0 +1,7 @@
+import { maybeTransformSafe } from '../safe'
+
+export transformSafeExprs(programPath) ->
+  programPath.traverse({
+    CallExpression(path): void -> path~maybeTransformSafe()
+    MemberExpression(path): void -> path~maybeTransformSafe()
+  })

src/safe.lsc

@@ -1,8 +1,7 @@
 import t from './types'
 import atNode from 'ast-loc-utils/lib/placeAtNode'
 import { hoistRef, isSimple } from './ref'
-import is, { isa } from './is'
-import { ensureBlockArrowFunctionExpression } from './functions'
+import { isa } from './is'
 
 import { getLoc, placeTreeAtLocWhenUnplaced as allAtLoc } from 'ast-loc-utils'
 
@@ -15,6 +14,7 @@ findReplacementPath(path) ->
     if key == "left" and parentPath~isa("AssignmentExpression"): false
     elif key == "object" and parentPath~isa("MemberExpression"): false
     elif key == "callee" and (parentPath~isa("CallExpression") or parentPath~isa("NewExpression")): false
+    elif key == 0 and path.listKey == "arguments" and path.parent.tilde: false // lift past tilde calls
     elif key == "argument" and parentPath~isa("UpdateExpression"): false
     elif key == "argument" and (parentPath~isa("UnaryExpression") and parentPath.node.operator == "delete"): false
     else: true

test/fixtures/safe-call-expression/complex-expr/expected.js

@@ -1,3 +1,3 @@
 var _obj;
 
-(typeof (_obj = a(b, c != null, d)).e !== "function" ? void 0 : _obj.e(f, g != null)) ? h : typeof k.l !== "function" ? void 0 : k.l(typeof i !== "function" ? void 0 : i(j), m != null);
+(typeof (_obj = a(b, c != null, d)).e !== "function" ? void 0 : _obj.e(f, g != null)) ? h : typeof k.l !== "function" ? void 0 : typeof i !== "function" ? void 0 : k.l(i(j), m != null);

test/fixtures/safe-member-expression/calls-after/expected.js

@@ -1,11 +1,11 @@
-var _ref, _ref2, _ref3;
+var _a$b, _a$b$c, _c;
 
 a == null ? void 0 : a.b();
 
-(_ref = a == null ? void 0 : a.b()) == null ? void 0 : _ref.c().d.e();
+a == null ? void 0 : (_a$b = a.b()) == null ? void 0 : _a$b.c().d.e();
 
-(_ref2 = a == null ? void 0 : a.b().c) == null ? void 0 : _ref2.d().e.f();
+a == null ? void 0 : (_a$b$c = a.b().c) == null ? void 0 : _a$b$c.d().e.f();
 
 a == null ? void 0 : c(a.b);
 
-(_ref3 = a == null ? void 0 : c(a.b)) == null ? void 0 : e(_ref3.d);
+(_c = a == null ? void 0 : c(a.b)) == null ? void 0 : e(_c.d);

test/fixtures/safe-member-expression/tilde-call/actual.js

@@ -0,0 +1 @@
+a?.b~c()

test/fixtures/safe-member-expression/tilde-call/expected.js

@@ -0,0 +1 @@
+a == null ? void 0 : c(a.b);