Multiple targets support fixed in followAssignmentsChain(); some tests added.

python/src/com/jetbrains/python/psi/PyUtil.java

@@ -621,10 +621,9 @@ public class PyUtil {
         else if (ret == null && elt instanceof PyElement) { // remember this result, but a reference may be the next resolve result
           ret = (PyElement)elt;
         }
-        else { // not a reassignment, not anything from Python; no point to continue
-          break SEARCH;
-        }
       }
+      // all resolve results checked, reassignment not detected, nothing more to do
+      break;
     }
     return ret;
   }

python/src/com/jetbrains/python/psi/impl/PyAssignmentStatementImpl.java

@@ -24,6 +24,7 @@ import com.intellij.psi.PsiWhiteSpace;
 import com.intellij.psi.ResolveState;
 import com.intellij.psi.scope.PsiScopeProcessor;
 import com.intellij.psi.util.PsiTreeUtil;
+import com.intellij.util.SmartList;
 import com.intellij.util.containers.HashMap;
 import com.jetbrains.python.PyElementTypes;
 import com.jetbrains.python.psi.*;
@@ -81,31 +82,16 @@ public class PyAssignmentStatementImpl extends PyElementImpl implements PyAssign
 
   @NotNull
   public List<Pair<PyExpression, PyExpression>> getTargetsToValuesMapping() {
-    List<Pair<PyExpression, PyExpression>> ret = new ArrayList<Pair<PyExpression, PyExpression>>();
-    List<PyExpression> lhses = new ArrayList<PyExpression>(1);
-    PyExpression rhs = null;
-    // extract all LHSes and RHS
-    boolean seen_eq = false;
-    for (PsiElement child = this.getFirstChild(); child != null; child = child.getNextSibling()) {
-      if (child instanceof PsiWhiteSpace) continue;
-      if ("=".equals(child.getText())) seen_eq = true;
-      if (child instanceof PyExpression) {
-        PyExpression expr = (PyExpression)child;
-        if (seen_eq) {
-          if (rhs != null) { // more than one RHS is clearly a parsing error, return nothing.
-            ret.clear();
-            return ret;
-          }
-          rhs = expr;
-        }
-        else lhses.add(expr);
+    List<Pair<PyExpression, PyExpression>> ret = new SmartList<Pair<PyExpression, PyExpression>>();
+    if (!PsiTreeUtil.hasErrorElements(this)) { // no parse errors
+      PyExpression[] constituents = PsiTreeUtil.getChildrenOfType(this, PyExpression.class); // "a = b = c" -> [a, b, c]
+      if (constituents != null && constituents.length > 1) {
+        PyExpression rhs = constituents[constituents.length - 1]; // last
+        List<PyExpression> lhses = new ArrayList<PyExpression>(constituents.length - 1);
+        for (int i = 0; i < constituents.length - 1; i += 1) lhses.add(constituents[i]); // copy all but last; most often it's one element.
+        for (PyExpression lhs : lhses) mapToValues(lhs, rhs, ret);
       }
     }
-    if (lhses.size() == 0) { // no LHS, must be incorrectly parsed
-      ret.clear();
-      return ret;
-    }
-    for (PyExpression lhs : lhses) mapToValues(lhs, rhs, ret);
     return ret;
   }
 

python/src/com/jetbrains/python/psi/impl/PyCallExpressionHelper.java

@@ -45,6 +45,7 @@ public class PyCallExpressionHelper {
     if (callee instanceof PyReferenceExpression) {
       PyReferenceExpression ref = (PyReferenceExpression)callee;
       PsiElement resolved = PyUtil.followAssignmentsChain(ref);
+      if (resolved instanceof PyClass) resolved = ((PyClass)resolved).findMethodByName(PyNames.INIT); // class to constructor call
       if (resolved instanceof PyFunction) {
         EnumSet<PyCallExpression.Flag> flags = EnumSet.noneOf(PyCallExpression.Flag.class);
         int implicit_offset = 0;

python/testData/paramInfo/ReassignedClassInit.py

@@ -0,0 +1,7 @@
+class Bar:
+  def __init__(self, a, b):
+    pass
+
+Boar = Bambr = Bar
+
+Bambr(<arg1>1, <arg2>2)

python/testData/paramInfo/ReassignedFunction.py

@@ -0,0 +1,7 @@
+def foo(a, b):
+  pass
+
+zoo = foo
+moo, n = zoo, 1
+
+moo(<arg1>1, <arg2>n)

python/testData/paramInfo/ReassignedInstanceMethod.py

@@ -0,0 +1,8 @@
+class Foo:
+  def moo(self, a, b, c):
+    pass
+
+foo = Foo()
+qoo = foo
+
+qoo.moo(<arg1>1, <arg2>2, <arg3>"bamboo")

python/testSrc/com/jetbrains/python/PyParameterInfoTest.java

@@ -213,7 +213,32 @@ public class PyParameterInfoTest extends MarkedTestCase {
     feignCtrlP(marks.get("<arg2>").getTextOffset()).check("self,a", new String[]{"a"});
   }
 
-  // TODO: add method tests with decorators when a mock SDK is available 
+  public void testReassignedFunction() throws Exception {
+    Map<String, PsiElement> marks = loadTest();
+    assertEquals("Test data sanity", marks.size(), 2);
+
+    feignCtrlP(marks.get("<arg1>").getTextOffset()).check("a,b", new String[]{"a,"});
+    feignCtrlP(marks.get("<arg2>").getTextOffset()).check("a,b", new String[]{"b"});
+  }
+
+  public void testReassignedInstanceMethod() throws Exception {
+    Map<String, PsiElement> marks = loadTest();
+    assertEquals("Test data sanity", marks.size(), 3);
+
+    feignCtrlP(marks.get("<arg1>").getTextOffset()).check("self,a,b,c", new String[]{"a,"}, new String[]{"self,"});
+    feignCtrlP(marks.get("<arg2>").getTextOffset()).check("self,a,b,c", new String[]{"b,"}, new String[]{"self,"});
+    feignCtrlP(marks.get("<arg3>").getTextOffset()).check("self,a,b,c", new String[]{"c"}, new String[]{"self,"});
+  }
+
+  public void testReassignedClassInit() throws Exception {
+    Map<String, PsiElement> marks = loadTest();
+    assertEquals("Test data sanity", marks.size(), 2);
+
+    feignCtrlP(marks.get("<arg1>").getTextOffset()).check("self,a,b", new String[]{"a,"}, new String[]{"self,"});
+    feignCtrlP(marks.get("<arg2>").getTextOffset()).check("self,a,b", new String[]{"b"}, new String[]{"self,"});
+  }
+
+  // TODO: add method tests with decorators when a mock SDK is available
 
   /**
    * Imitates pressing of Ctrl+P; fails if results are not as expected.