diff --git a/clang/lib/StaticAnalyzer/Core/CallEvent.cpp b/clang/lib/StaticAnalyzer/Core/CallEvent.cpp
--- a/clang/lib/StaticAnalyzer/Core/CallEvent.cpp
+++ b/clang/lib/StaticAnalyzer/Core/CallEvent.cpp
@@ -172,23 +172,9 @@
   if (!D)
     return nullptr;
 
-  // TODO: For now we skip functions without definitions, even if we have
-  // our own getDecl(), because it's hard to find out which re-declaration
-  // is going to be used, and usually clients don't really care about this
-  // situation because there's a loss of precision anyway because we cannot
-  // inline the call.
-  RuntimeDefinition RD = getRuntimeDefinition();
-  if (!RD.getDecl())
-    return nullptr;
-
   AnalysisDeclContext *ADC =
       LCtx->getAnalysisDeclContext()->getManager()->getContext(D);
 
-  // TODO: For now we skip virtual functions, because this also rises
-  // the problem of which decl to use, but now it's across different classes.
-  if (RD.mayHaveOtherDefinitions() || RD.getDecl() != ADC->getDecl())
-    return nullptr;
-
   return ADC;
 }
 
diff --git a/clang/test/Analysis/explain-svals.cpp b/clang/test/Analysis/explain-svals.cpp
--- a/clang/test/Analysis/explain-svals.cpp
+++ b/clang/test/Analysis/explain-svals.cpp
@@ -98,7 +98,7 @@
 } // end of anonymous namespace
 
 void test_6() {
-  clang_analyzer_explain(conjure_S()); // expected-warning-re{{{{^lazily frozen compound value of temporary object constructed at statement 'conjure_S\(\)'$}}}}
+  clang_analyzer_explain(conjure_S()); // expected-warning-re{{{{^lazily frozen compound value of 1st parameter of function 'clang_analyzer_explain\(\)'$}}}}
   clang_analyzer_explain(conjure_S().z); // expected-warning-re{{{{^value derived from \(symbol of type 'int' conjured at statement 'conjure_S\(\)'\) for field 'z' of temporary object constructed at statement 'conjure_S\(\)'$}}}}
 }
 
diff --git a/clang/test/Analysis/temporaries.cpp b/clang/test/Analysis/temporaries.cpp
--- a/clang/test/Analysis/temporaries.cpp
+++ b/clang/test/Analysis/temporaries.cpp
@@ -890,12 +890,9 @@
 public:
   ~C() {
     glob = 1;
-    // FIXME: Why is destructor not inlined in C++17
     clang_analyzer_checkInlined(true);
 #ifdef TEMPORARY_DTORS
-#if __cplusplus < 201703L
-    // expected-warning@-3{{TRUE}}
-#endif
+    // expected-warning@-2{{TRUE}}
 #endif
   }
 };
@@ -914,16 +911,11 @@
   // temporaries returned from functions, so we took the wrong branch.
   coin && is(get()); // no-crash
   if (coin) {
-    // FIXME: Why is destructor not inlined in C++17
     clang_analyzer_eval(glob);
 #ifdef TEMPORARY_DTORS
-#if __cplusplus < 201703L
-    // expected-warning@-3{{TRUE}}
-#else
-    // expected-warning@-5{{UNKNOWN}}
-#endif
+    // expected-warning@-2{{TRUE}}
 #else
-    // expected-warning@-8{{UNKNOWN}}
+    // expected-warning@-4{{UNKNOWN}}
 #endif
   } else {
     // The destructor is not called on this branch.
diff --git a/clang/unittests/StaticAnalyzer/ParamRegionTest.cpp b/clang/unittests/StaticAnalyzer/ParamRegionTest.cpp
--- a/clang/unittests/StaticAnalyzer/ParamRegionTest.cpp
+++ b/clang/unittests/StaticAnalyzer/ParamRegionTest.cpp
@@ -16,6 +16,15 @@
 namespace {
 
 class ParamRegionTestConsumer : public ExprEngineConsumer {
+  void checkForSameParamRegions(MemRegionManager &MRMgr,
+                                const StackFrameContext *SFC,
+                                const ParmVarDecl *PVD) {
+    for (const auto *D2: PVD->redecls()) {
+      const auto *PVD2 = cast<ParmVarDecl>(D2);
+      assert(MRMgr.getVarRegion(PVD, SFC) == MRMgr.getVarRegion(PVD2, SFC));
+    }
+  }
+
   void performTest(const Decl *D) {
     StoreManager &StMgr = Eng.getStoreManager();
     MemRegionManager &MRMgr = StMgr.getRegionManager();
@@ -29,6 +38,7 @@
           assert(isa<NonParamVarRegion>(Reg));
         else
           assert(isa<ParamVarRegion>(Reg));
+        checkForSameParamRegions(MRMgr, SFC, P);
       }
     } else if (const auto *CD = dyn_cast<CXXConstructorDecl>(D)) {
       for (const auto *P : CD->parameters()) {
@@ -37,6 +47,7 @@
           assert(isa<NonParamVarRegion>(Reg));
         else
           assert(isa<ParamVarRegion>(Reg));
+        checkForSameParamRegions(MRMgr, SFC, P);
       }
     } else if (const auto *MD = dyn_cast<ObjCMethodDecl>(D)) {
       for (const auto *P : MD->parameters()) {
@@ -45,6 +56,7 @@
           assert(isa<NonParamVarRegion>(Reg));
         else
           assert(isa<ParamVarRegion>(Reg));
+        checkForSameParamRegions(MRMgr, SFC, P);
       }
     }
   }
@@ -71,7 +83,10 @@
 TEST(ParamRegion, ParamRegionTest) {
   EXPECT_TRUE(
       tooling::runToolOnCode(std::make_unique<ParamRegionTestAction>(),
-                             R"(void foo(int n) {
+                             R"(void foo(int n);
+                                void baz(int p);
+
+                                void foo(int n) {
                                   auto lambda = [n](int m) {
                                     return n + m;
                                   };
@@ -90,7 +105,10 @@
 
                                 void baz(int p) {
                                   S s(p);
-                                })"));
+                                }
+
+                                void bar(int l);
+                                void baz(int p);)"));
   EXPECT_TRUE(
       tooling::runToolOnCode(std::make_unique<ParamRegionTestAction>(),
                              R"(@interface O